Image forming apparatus

Abstract

An image forming apparatus includes a replaceable unit including a driven portion and an apparatus body to which the replaceable unit is detachably attached. The device body includes: (i) a driving unit including a driving source and an output portion; (ii) a first drive transmission portion connected to the output portion and the replaceable unit; and (iii) a second drive transmission portion including an admitting mechanism and connected to the output portion and the replaceable unit. The permitting mechanism includes a first rotating member and a second rotating member and is configured to transmit a driving force between the first rotating member and the second rotating member and permit a change in a ratio between a first angular velocity of the first rotating member and a second angular velocity of the second rotating member.

Description

Technical Field

[0001] This disclosure relates to an image forming apparatus for forming an image on a recording material. Background Technology

[0002] Japanese Patent Application Publication No. 2020-154313 discloses a photosensitive drum in a device body that can be attached to and detached from the device body of an image forming apparatus. The drum is driven to rotate by the driving force of a motor provided in the device body, while receiving braking force generated by a braking member provided in the device body.

[0003] In the image forming apparatus described in the aforementioned documents, the braking member is attached to a support shaft of a frame fixed to the apparatus body. Furthermore, in the image forming apparatus described in the aforementioned documents, the driving force of the motor is transmitted via a non-circular transmission path that extends sequentially through a drum drive connector, a drum connector, a braking engagement member, and a braking member, and terminates at the braking member. Summary of the Invention

[0004] This disclosure provides a new technique related to the driving of units in an image forming apparatus.

[0005] According to one aspect of this disclosure, an image forming apparatus includes: a replaceable unit including a driven portion; and an apparatus body to which the replaceable unit is detachably attached, the apparatus body including: (i) a drive unit including a drive source configured to generate a drive force and an output portion configured to output the drive force; (ii) a first drive transmission portion connected to the output portion and the replaceable unit; and (iii) a second drive transmission portion including a permissive mechanism and connected to the output portion and the replaceable unit, the permissive mechanism including a first rotating member and a second rotating member and configured to transmit a drive force between the first rotating member and the second rotating member and to permissive a change in the ratio between a first angular velocity of the first rotating member and a second angular velocity of the second rotating member, wherein the drive force transmission path includes a closed loop including the driven portion, the output portion, the first drive transmission portion and the second drive transmission portion, and wherein the first drive transmission portion and the second drive transmission portion are configured such that when the driven portion is driven by the drive source, the first angular velocity is different from the second angular velocity.

[0006] According to another aspect of this disclosure, an image forming apparatus includes: a replaceable unit including a driven portion; and an apparatus body to which the replaceable unit is detachably attached, the apparatus body including: (i) a drive unit including a drive source configured to generate a drive force and an output portion configured to output the drive force; (ii) a first drive transmission portion connected to the output portion and the replaceable unit; and (iii) a second drive transmission portion including a differential mechanism and connected to the output portion and the replaceable unit, the differential mechanism including a first rotating member and a second rotating member and configured to allow the first rotating member and the second rotating member to rotate relative to each other, wherein the drive force transmission path includes a closed loop including the driven portion, the output portion, the first drive transmission portion and the second drive transmission portion, wherein the first drive transmission portion and the second drive transmission portion are configured such that, when the driven portion is driven by the drive source, a first angular velocity of the first rotating member is different from a second angular velocity of the second rotating member, and wherein the first rotating member and the second rotating member are configured to rotate about the same rotation axis.

[0007] According to another aspect of this disclosure, an image forming apparatus includes: a unit including a driven portion; a driving unit including a driving source configured to generate a driving force and an output portion configured to output the driving force; a first driving transmission portion connected to the output portion and the unit; and a second driving transmission portion including a planetary gear mechanism and connected to the output portion and the unit, wherein the transmission path of the driving force includes a closed loop including the driven portion, the output portion, the first driving transmission portion and the second driving transmission portion.

[0008] The features of this disclosure will become clear from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is given by way of example. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the cross-sectional configuration of the image forming apparatus according to the first embodiment.

[0010] Figure 2 This is a schematic diagram showing the state of the door of the image forming apparatus according to the first embodiment being open.

[0011] Figure 3 This is a perspective view of the box according to the first embodiment.

[0012] Figure 4 This is an enlarged view of a portion of the box according to the first embodiment.

[0013] Figures 5A to 5C These are explanatory diagrams of the body driving system according to the first embodiment.

[0014] Figure 6A and Figure 6B These are exploded views of the drive transmission unit according to the first embodiment.

[0015] Figure 7A This is a side view of the drive transmission unit according to the first embodiment.

[0016] Figure 7B This is a cross-sectional unfolded view of the drive transmission unit according to the first embodiment.

[0017] Figures 8A to 8C These are perspective views of a portion of the drive transmission unit according to the first embodiment.

[0018] Figure 9 This is a cross-sectional view of the drive transmission unit and drum connector according to the first embodiment.

[0019] Figure 10A This is a diagram showing the engagement state of the drive transmission unit and the drum connector according to the first embodiment.

[0020] Figure 10B This is a diagram showing the engagement state of the drive transmission unit and the drum connector according to the second embodiment.

[0021] Figure 11A and Figure 11B These are diagrams illustrating the operation of the body drive system according to the first embodiment.

[0022] Figure 12 This is a cross-sectional view showing the operation of the body drive system according to the first embodiment.

[0023] Figure 13A This is a model diagram of the body driving system according to the first embodiment.

[0024] Figure 13B It is a model diagram of the ontology-driven system based on the first reference example.

[0025] Figure 13C It is a model diagram of the ontology-driven system based on the second reference example.

[0026] Figure 14A and Figure 14B These are diagrams illustrating the operation of the body drive system according to the second embodiment.

[0027] Figure 15This is a cross-sectional unfolded view showing the operation of the body drive system according to the second embodiment.

[0028] Figure 16 This is a model diagram of the body driving system according to the second embodiment.

[0029] Figures 17A to 17D These are schematic diagrams of the body drive system according to the second embodiment.

[0030] Figure 18A and Figure 18B These are diagrams illustrating the operation of the body drive system according to the third embodiment.

[0031] Figure 19 This is a cross-sectional unfolded view showing the operation of the body drive system according to the third embodiment.

[0032] Figure 20 This is a model diagram of the body driving system according to the third embodiment.

[0033] Figure 21A This is a model diagram of the body driving system according to the fourth embodiment.

[0034] Figure 21B This is a schematic diagram of a planetary gear mechanism according to the fourth embodiment.

[0035] Figure 22A and Figure 22B These are diagrams illustrating the operation of the body drive system according to another embodiment. Detailed Implementation

[0036] Embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0037] First Embodiment

[0038] Reference Figure 1 and Figure 2 A printer 1 is described as an image forming apparatus according to an embodiment (first embodiment) of the present disclosure. Figure 1 This is a schematic diagram showing the overall cross-sectional configuration of the printer 1 according to this embodiment. Figure 2 This is a schematic diagram showing the printer 1 with its door 20 open.

[0039] The printer 1 according to this embodiment is a color laser beam printer of an electrophotographic system that forms images on a sheet S. Various sheet materials of different sizes and materials can be used as the recording material (recording medium). Examples of sheet materials include paper sheets (e.g., ordinary paper sheets and cardboard), surface-treated sheet materials (e.g., coated paper sheets), irregularly shaped sheet materials (e.g., envelope and index paper sheets), plastic films, and fabrics.

[0040] Printer 1 includes a device body (casing) 1A, a scanner (exposure unit) 2, a controller 3, and a door (opening / closing member) 20 that can be opened and closed relative to the device body 1A. Furthermore, printer 1 includes a sheet feed section 30, a transfer unit (transfer device) 40, a tray unit (moving unit, support unit) 50, and a fixing unit 80. The portion including the device body 1A and the door 20 may also be referred to as the main frame 100. The main frame 100 includes the external portion of printer 1.

[0041] The main body of the equipment 1A includes a scanner 2, a controller 3, a sheet feed section 30, a transfer unit 40, a tray unit 50, and a fixing unit 80.

[0042] The sheet feeding section 30 includes a stacking tray 31 and a feed roller 32 serving as a feeding member. Sheets S are stacked on the stacking tray 31, and the feed roller 32 feeds the sheets S. The stacking tray 31 is configured to allow passage along the direction of the opening door 20 ( Figure 1 (From center to right) Pull out the stacking tray 31 from the device body 1A to replenish the sheet S.

[0043] The tray unit 50 includes a tray (support member, drawer) 51 and boxes PY, PM, PC, and PK. Boxes PY, PM, PC, and PK are detachably attached to the tray 51. In this embodiment, boxes PY, PM, PC, and PK can be attached to and detached from the tray 51 independently of each other.

[0044] Cassettes PY, PM, PC, and PK store toners (developers) in yellow (Y), magenta (M), cyan (C), and black (K), respectively. Except for the colors of the toners stored, cassettes PY, PM, PC, and PK have the same configuration. Therefore, the configuration and operation of one of cassettes PY, PM, PC, and PK will be described, and descriptions of the other cassettes may be omitted. Furthermore, when it is not necessary to distinguish cassettes PY, PM, PC, and PK from one another, they can simply be referred to as cassette P. The tray unit 50 can be said to include a plurality of cassettes P and a tray 51, wherein the plurality of cassettes P are detachably attached to the tray 51.

[0045] Box P is an example of a replaceable unit that is detachably (replaceably) attached to the device body 1A. In this embodiment, box P is part of tray unit 50 and is detachably attached to the device body 1A via tray 51. However, box P may be detachably attached to the device body 1A without tray 51 therein.

[0046] Alternatively, instead of cartridge P, a unit (module, slave unit, slave module) with similar functionality to cartridge P can be attached to the device body 1A in a manner that does not require attachment and removal (replacement) by the user. In other words, cartridge P is an example of a "unit" that cannot necessarily be removed from the device body 1A. It should be noted that in the case of cartridge P (fixed processing unit) being non-removably fixed to the device body 1A, toner can be replenished to the developing unit from outside the printer 1 using a replenishment container.

[0047] In this embodiment, the tray unit 50 includes multiple photosensitive drums (image carrying members) 61, multiple charging rollers 62 (charging members), and multiple developing rollers 71 (developer carrying members). Specifically, the tray unit 50 of this embodiment includes four photosensitive drums 61, four charging rollers 62, and four developing rollers 71. The rotation axis directions of the photosensitive drums 61, the rotation axis directions of the developing rollers 71, and the rotation axis directions of the charging rollers 62 are parallel. The photosensitive drums 61 are an example of rotating members rotatably disposed in the cartridge P.

[0048] In tray unit 50, the portion forming a black (K) image will be referred to as the black station (first station), and the photosensitive drum 61, developing roller 71, and charging roller 62 of the first station will be referred to as the first photosensitive drum, the first developing roller, and the first charging roller, respectively. In tray unit 50, the portion forming a cyan (C) image will be referred to as the cyan station (second station), and the photosensitive drum 61, developing roller 71, and charging roller 62 of the second station will be referred to as the second photosensitive drum, the second developing roller, and the second charging roller, respectively. In tray unit 50, the portion forming a magenta (M) image will be referred to as the magenta station (third station), and the photosensitive drum 61, developing roller 71, and charging roller 62 of the third station will be referred to as the third photosensitive drum, the third developing roller, and the third charging roller, respectively. In tray unit 50, the portion forming a yellow (Y) image will be referred to as the yellow station (fourth station), and the photosensitive drum 61, developing roller 71, and charging roller 62 of the fourth station will be referred to as the fourth photosensitive drum, the fourth developing roller, and the fourth charging roller, respectively.

[0049] Box PK, Box PC, Box PM, and Box PY are respectively attached to the black station, cyan station, magenta station, and yellow station. In this embodiment, Box PK, Box PC, Box PM, and Box PY will be referred to as the first box, the second box, the third box, and the fourth box, respectively.

[0050] It should be noted that ordinal numbers such as first, second, third, and fourth are used for ease of description. The photosensitive drum 61, charging roller 62, and developing roller 71 only need to be located in either cartridge P or tray 51. In this embodiment, cartridge P includes the photosensitive drum 61, charging roller 62, and developing roller 71.

[0051] The transfer unit 40 includes a belt 41, a primary transfer roller 42, a cleaning section 43, a drive roller 46 for driving the belt 41, and a tension roller 47. In the printer 1 of this embodiment, an optical sensor 44 is provided for detecting the toner image transferred onto the belt 41. In this embodiment, the belt 41 is positioned below and abuts against four photosensitive drums 61, such that a primary transfer portion is formed between each portion of the belt 41 and the photosensitive drums 61. Additionally, the printer 1 includes a secondary transfer roller 45 that abuts against the belt 41 to form a secondary transfer portion. The secondary transfer portion is formed between the belt 41 and the secondary transfer roller 45. The rotation axis directions of the primary transfer roller 42, the drive roller 46, the tension roller 47, and the secondary transfer roller 45 are parallel. An alignment roller pair 4 is positioned upstream of the secondary transfer portion.

[0052] The fixing unit 80 includes a fixing section 81 and a switching guide 5. The fixing unit 80 is housed within the device body 1A. The fixing section 81 is a unit of a thermal fixing system that heats and presses the image on the sheet S while it is being transported during the image forming operation. In this embodiment, the fixing section 81 includes a heating section (heating roller) with a heater and a pressurizing section (pressurizing roller).

[0053] Image forming operations

[0054] Reference Figure 1 This describes an image forming operation, which is a series of operations for forming an image on a sheet S while the printer 1 is feeding the sheet S. The controller 3 of the printer 1 initiates the image forming operation based on image information received from an external host device 900. The external host device 900 is, for example, a personal computer, an image reader, or a fax machine.

[0055] When the image forming operation begins, rotational drive is initiated for each photosensitive drum 61 and belt 41. A charging voltage is applied to each charging roller 62, thereby charging the surface of the corresponding photosensitive drum 61. Based on the image information, the scanner 2 is driven to irradiate the photosensitive drum 61 with a laser from the scanner 2, thereby exposing the surface of the photosensitive drum 61. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 61.

[0056] The developing roller 71 rotates while carrying toner. A developing voltage is applied to the developing roller 71. The electrostatic latent image formed on the photosensitive drum 61 is developed by the toner supplied from the developing roller 71, thereby forming a toner image on the surface of the photosensitive drum 61. When forming a panchromatic image, toner images of corresponding colors are formed on the four photosensitive drums 61. In this embodiment, the developing roller 71 develops the electrostatic latent image while in contact with the photosensitive drum 61; however, the developing roller 71 can also develop the electrostatic latent image with a gap between the developing roller 71 and the photosensitive drum 61.

[0057] It should be noted that in this embodiment, the developing roller 71 can move between a contact position where the developing roller 71 abuts against the photosensitive drum 61 and a separation position where the developing roller 71 is separated from the photosensitive drum 61. Specifically, the state in which the developing roller 71 is in the contact position and the state in which the developing roller 71 is in the separation position are switched by a switching unit provided in the device body 1A. As a result, the developing roller 71 can be separated from the photosensitive drum 61 when no image forming operation is performed.

[0058] Furthermore, printer 1 can form monochrome images while the developing roller 71 and photosensitive drum 61 corresponding to cartridge PK are in contact with each other and are separated from each other, respectively, by the developing roller 71 and photosensitive drum 61 corresponding to cartridges PY, PM, and PC. Alternatively, printer 1 can form panchromatic images while the photosensitive drum 61 corresponding to cartridges PY, PM, PC, and PK is in contact with the belt 41.

[0059] In the primary transfer section, the toner image formed on each photosensitive drum 61 is transferred by the primary transfer roller 42 onto the belt 41 and conveyed toward the secondary transfer section formed by the belt 41 and the secondary transfer roller 45.

[0060] Meanwhile, a transport path (first path, first transport path) 1c is formed in the device body 1A, through which the sheet S moving toward the fixing unit 80 passes. Furthermore, a double-sided transport path (second path, second transport path) 20a is formed in the door 20, through which the sheet S that has already passed the fixing unit 80 passes. The door 20 covers the transport path 1c when closed. As a result of opening the door 20, the transport path 1c and the double-sided transport path 20a are exposed to the outside of the printer 1. Figure 2 ).

[0061] In parallel with the formation of the toner image described above, in the sheet feeding section 30, a sheet S is fed from the sheet S stacked on the stacking tray 31 via the feed roller 32 at a predetermined time. The fed sheet S is conveyed toward the secondary transfer section via the conveyor path 1c. In the secondary transfer section, the toner image is transferred from the belt 41 onto the sheet S. Toner not transferred onto the sheet S is removed from the belt 41 by a cleaning scraper (cleaning member) provided in the cleaning section 43.

[0062] In the secondary transfer section, the toner image has been transferred onto the sheet S, which is then conveyed toward the fixing unit 80. In the fixing unit 80, the sheet S is heated and pressurized in the fixing section 81, thus fixing the toner image onto the sheet S. The sheet S, onto which the toner image has been fixed, is then conveyed toward the switching guide 5, which serves as the path switching section.

[0063] The switching guide 5 can be moved to a discharge position and a reverse position. In the discharge position, the switching guide 5 guides the sheet S, which has passed through the fixing section 81, toward the discharge path 1d. In the reverse position, the switching guide 5 guides the sheet S toward the reverse transport path 1e. In the case of single-sided printing where an image is formed on only one surface of the sheet S, the sheet S is guided by the switching guide 5 to the discharge path 1d and discharged onto the discharge tray 1f formed in the upper part of the device body 1A. In contrast, in the case of double-sided printing where an image is formed on each of the first and second surfaces of the sheet S, the sheet S, whose image has been formed on its first surface by the secondary transfer section and the fixing section 81, is guided by the switching guide 5 to the reverse transport path 1e. After the sheet S is guided to the reverse transport path 1e, the transport direction of the sheet S is reversed, and the sheet S is transported again toward the secondary transfer section via the double-sided transport path 20a formed in the gate 20. Then, the sheet S, on which the image has been formed on its second surface by the secondary transfer section and the fixing section 81, is guided by the switching guide 5 to the discharge path 1d and discharged onto the discharge tray 1f.

[0064] box

[0065] Reference Figure 3 and Figure 4 Describe the configuration of box P. Figure 3 This is a perspective view of the entire box P. Figure 4 This is a perspective view near the drum connector 63. The direction of the rotation axis of the photosensitive drum 61 included in the cartridge P will be referred to as the longitudinal direction of the cartridge P. Note that "photosensitive drum 61" in the following description refers to any one of one or more (four in this embodiment) photosensitive drums 61 included in the printer 1.

[0066] like Figure 3 As shown, cartridge P consists of a drum unit 60 and a developing unit 70. A first side cover 66 and a second side cover 67 are fixed to the corresponding ends of the drum unit 60 along the longitudinal direction of cartridge P. The developing unit is rotatably supported by the first side cover 66 and the second side cover 67.

[0067] The drum unit 60 comprises a photosensitive drum 61, a charging roller 62, a drum frame member 65 serving as a first frame member, etc. A drum connector 63 and a drum flange 64 are fixed to the photosensitive drum 61. The drum connector 63 is rotatably supported by a first side cover 66, and the drum flange 64 is rotatably supported by a second side cover 67. In addition to these, a cleaning portion (e.g., a cleaning blade, etc.) for removing residual toner from the surface of the photosensitive drum 61 may be provided in the drum unit 60. The drum unit 60 of this embodiment does not include a cleaning portion.

[0068] The developing unit 70 comprises a developing roller 71, a toner supply roller, a developing blade, a developing connector 72, and a developing frame member 73. The toner supply roller supplies toner from the toner storage space formed inside the developing frame member 73 to the developing roller 71. The developing blade abuts against the outer peripheral surface of the developing roller 71 with a predetermined contact pressure, controlling the layer thickness of the toner carried on the developing roller 71 and rubbing the toner to charge it. The developing connector 72 is a drive input section through which the developing unit 70 receives driving force from the device body 1A.

[0069] The drum connector 63 engages with the drive transmission unit 200 of the device body 1A, which will be described later, and rotates by receiving the driving force of the motor 301. In this embodiment, the drum connector 63 is arranged coaxially with the photosensitive drum 61, but the drum connector 63 may be a component that rotates about an axis different from the axis of rotation of the photosensitive drum 61.

[0070] like Figure 4 As shown, the drum connector 63 includes a circular hole portion 63a, a first force receiving portion 63b, and a second force receiving portion 63c. The circular hole portion 63a is configured to engage with the positioning boss 180i (FIG. 6) of the drive transmission unit 200. The first force receiving portion 63b is configured to receive driving force from the drive transmission unit 200. The second force receiving portion 63c is configured to receive braking force from the drive transmission unit 200.

[0071] In this embodiment, both the first force receiving portion 63b and the second force receiving portion 63c are provided on the protrusion 63p formed at the end portion in the axial direction of the drum connector 63. The first force receiving portion 63b is the surface of the protrusion 63p facing upstream of the normal rotation direction A1, and the second force receiving portion 63c is the surface of the protrusion 63p facing downstream of the normal rotation direction A1.

[0072] As described above, the cartridge P includes a driven portion driven by a motor 301. The driven portion includes a force receiving portion and a driving target. The force receiving portion engages with a component included in the body drive system 1D of the device body 1A and receives force from the body drive system 1D. The driving target is driven by the force transmitted to it via the force receiving portion. In this embodiment, the force receiving portion of the cartridge P is the first force receiving portion 63b and the second force receiving portion 63c of the drum connector 63. The driving target of the motor 301 in the cartridge P of this embodiment includes the photosensitive drum 61.

[0073] It should be noted that the driving target of the box P can be a component different from the photosensitive drum 61.

[0074] The driven portion of cartridge P includes a rotating member, and the direction of rotation of the rotating member during image formation (the first rotation direction) will be referred to as the normal rotation direction A1. That is, the driven portion of cartridge P includes a rotating member that rotates along the normal rotation direction A1 (the first rotation direction) when the driven portion of cartridge P is driven by the drive source (motor 301) of the device body 1A. Drum connector 63 is an example of a rotating member, but "rotating member" is not limited to drum connector 63 and can be, for example, a photosensitive drum 61.

[0075] In this embodiment, the housing P (replaceable unit, replaceable module) receives a driving force (first force) acting on the drum connector 63 (rotating member) in the normal rotation direction A1 (first rotation direction) from the first drive transmission portion 1D1 of the main body drive system 1D, which will be described later. Furthermore, the housing P (replaceable unit) in this embodiment receives a braking force (second force) acting on the drum connector 63 (rotating member) in the opposite direction (second rotation direction) to the normal rotation direction A1 from the second drive transmission portion 1D2 of the main body drive system 1D, which will be described later.

[0076] During image formation, the force (driving force, first force) received by the first force receiving portion 63b from the first drive transmission portion 1D1 of the body drive system 1D acts on the drum connector 63 along the normal rotation direction A1. During image formation, the force (braking force, second force) received by the second force receiving portion 63c from the second drive transmission portion 1D2 of the body drive system 1D acts on the drum connector 63 along a reverse rotation direction (second rotation direction) opposite to the normal rotation direction A1. That is, the housing P (replaceable unit) of this embodiment includes a first force receiving portion 63b (first surface) that receives the driving force (first force) from the first drive transmission portion 1D1 and a second force receiving portion 63c (second surface) that receives the braking force (second force) from the second drive transmission portion 1D2.

[0077] Body drive system

[0078] Next, the body drive system 1D provided in the device body 1A of this embodiment will be described. First, reference will be made to... Figure 13A Describe an overview of the 1D body-driven system, then refer to the main references. Figures 5A to 8C The configuration of the body driving system 1D in this embodiment is described.

[0079] Overview of the body drive system

[0080] Figure 13AThis is a model diagram illustrating the drive transmission path from motor 301 to box P in this embodiment. The device body 1A of this embodiment includes a body drive system 1D, which serves as a drive unit (drive mechanism) to drive box P, etc., using the driving force of motor 301. Motor 301 drives box P.

[0081] The main drive system 1D generally includes a drive unit 1Dd, a first drive transmission section 1D1 (first drive transmission path, first drive force transmitter), and a second drive transmission section 1D2 (second drive transmission path, second drive force transmitter). The drive unit 1Dd includes a motor 301 serving as a drive source for generating drive force, and a branch gear (output gear) 302 serving as an output section for outputting the drive force of the motor 301. The first drive transmission section 1D1 is connected to the branch gear 302 (output section) and the housing P (replaceable unit). The second drive transmission section 1D2 includes a torque limiter 410 (allowing mechanism, differential mechanism) and is connected to the branch gear 302 (output section) and the housing P (replaceable unit).

[0082] The first drive transmission section 1D1 and the second drive transmission section 1D2 are connected to each other via the cartridge P. Therefore, the transmission path of the driving force of the motor 301 in the printer 1 of this embodiment includes a closed loop. This closed loop includes the branch gear 302 (output section), the first drive transmission section 1D1, the second drive transmission section 1D2 including the torque limiter 410 (allowing mechanism, differential mechanism), and the drum connector 63 of the cartridge P (driven section, driven connector).

[0083] The first drive transmission section 1D1 and the second drive transmission section 1D2 each connect the branch gear 302 (output section) to the housing P in parallel. In other words, the first drive transmission section 1D1 and the second drive transmission section 1D2 each include a component (in this embodiment, the first drive gear 303 and the second drive gear 304) that engages with the branch gear 302 (output section). Furthermore, the first drive transmission section 1D1 and the second drive transmission section 1D2 each include a component that engages with the housing P (in this embodiment, the body-side connector 180 and the engaging components (204, 208)). In this embodiment, the first drive gear 303 and the second drive gear 304 directly engage with the branch gear 302, and the body-side connector 180 and the engaging components (204, 208) directly engage with the drum connector 63 (driven section).

[0084] The second drive transmission portion 1D2 of this embodiment can be divided into a motor-side transmission portion 1D2a (drive source-side transmission portion, drive source-side transmitter) and a box-side transmission portion 1D2b (unit-side transmission portion, unit-side transmitter) at the torque limiter 410. The motor-side transmission portion 1D2a is connected to the branch gear 302 and the inner ring 410b of the torque limiter 410. The box-side transmission portion 1D2b is connected to the outer ring 410a of the torque limiter 410 and the drum connector 63 of the box P.

[0085] It should be noted that the outer ring 410a can be connected to the motor-side transmission part 1D2a, and the inner ring 410b can be connected to the box-side transmission part 1D2b. In addition, the outer ring 410a and inner ring 410b of the torque limiter 410, or the component that rotates integrally with the outer ring 410a / inner ring 410b, can directly engage with the box P without any other gears or the like in between.

[0086] In this embodiment, the first drive transmission part 1D1 is located at the branch gear 302 and the drum connector 63 of the box P. Figure 4 The second drive transmission section 1D2 of this embodiment transmits force between the branch gear 302 and the inner ring 410b of the torque limiter 410. Furthermore, the box-side transmission section 1D2b of the second drive transmission section 1D2 of this embodiment transmits force between the outer ring 410a of the torque limiter 410 and the drum connector 63 of the box P.

[0087] The first drive transmission section 1D1 and the second drive transmission section 1D2 can transmit the driving force of the motor 301 to the drive target unit in the printer 1, excluding the cartridge P. In this embodiment, the motor-side transmission section 1D2a of the second drive transmission section 1D2 is connected to the load member 306 and can transmit the driving force of the motor 301 to the load member 306. For example, the load member 306 is a conveyor roller (e.g., feed roller 32 or alignment roller pair 4) for conveying the sheet S.

[0088] Configuration of the main drive system

[0089] The configuration of the ontology driving system 1D in this embodiment will be described. Figure 5A It is a diagram showing the main drive system 1D, and a combination of a perspective view of part of the main drive system 1D (drive transmission unit 200 and differential mechanism part 400) viewed from the front and a schematic diagram showing other components of the main drive system 1D. Figure 5B This is a perspective view of the drive transmission unit 200 and the differential mechanism section 400 as seen from the rear. Figure 5C This is an exploded perspective view of the differential mechanism section 400. Figure 6A This is an exploded perspective view of the drive transmission unit 200. Figure 6B This is an exploded perspective view showing a portion of the drive transmission unit 200 in an enlarged manner. Figure 7A This is a diagram of the drive transmission unit 200 and the differential mechanism section 400 as viewed from the front. Figure 7B It is along Figure 7A Figure 8 is a cross-sectional view of the drive transmission unit 200 and the differential mechanism portion 400, taken from line AA. Figure 8 is a perspective view of the body-side connecting member 180.

[0090] like Figure 5A As shown, the main drive system 1D includes a drive transmission unit 200, a gear system 300, and a differential mechanism 400.

[0091] like Figure 5A , Figure 6A , Figure 6B and Figure 7B As shown, the drive transmission unit 200 includes a body-side connector 180, a connecting gear 201, and a transmission shaft 209. Furthermore, the drive transmission unit 200 includes a bearing member 202, a first engagement member 204, a force transmission member 207, a second engagement member 208, a connecting spring 210, a braking engagement spring 211, and a spring retaining member 214.

[0092] like Figures 5A to 5C and Figure 7B As shown, the differential mechanism portion 400 includes a torque limiter 410, which includes an outer ring 410a and an inner ring 410b. Furthermore, the differential mechanism portion 400 includes a first differential gear 401, a second differential gear 402, an outer peripheral gear 403, a third differential gear 404, a fourth differential gear 405, a differential shaft 406, a coupling pin 407, and bearings 408 and 409.

[0093] like Figure 5A As shown, the gear train 300 includes a branch gear 302, a first drive gear 303, a second drive gear 304, and a load member gear 305. Furthermore, the gear train 300 includes one or more gears (not shown) that connect the first drive gear 303 to the connecting gear 201 of the drive transmission unit 200, and one or more gears (not shown) that connect the load member gear 305 to the fourth differential gear 405 of the differential mechanism section 400. Additionally, the gear train 300 may include one or more gears (not shown) that connect the second drive gear 304 to the load member gear 305. That is, in Figure 5A Gears connected by double-dotted lines can be connected by one or more gears.

[0094] The components of the drive transmission unit 200, the differential mechanism section 400, and the gear system 300 are the motor-side transmission section 1D2a and the box-side transmission section 1D2b of the first drive transmission section 1D1 and the second drive transmission section 1D2. Figure 13A The correspondence between them is as follows.

[0095] In this embodiment, the first drive transmission portion 1D1 includes a part of the gear train 300 (first drive gear 303) and a part of the drive transmission unit 200 (connecting gear 201 and body-side connecting member 180). The first drive transmission portion 1D1 may include one or more gears that connect the first drive gear 303 and the connecting gear 201.

[0096] In this embodiment, the motor-side transmission portion 1D2a of the second drive transmission portion 1D2 includes a portion of the gear train 300 (a second drive gear 304 and a load member gear 305) and a portion of the differential mechanism portion 400 (a third differential gear 404, a fourth differential gear 405, and a differential shaft 406). The motor-side transmission portion 1D2a of the second drive transmission portion 1D2 may include one or more gears that connect the second drive gear 304 to the load member gear 305 and one or more gears that connect the load member gear 305 to the fourth differential gear 405.

[0097] In this embodiment, the box-side transmission portion 1D2b of the second drive transmission portion 1D2 includes a part of the differential mechanism portion 400 (first differential gear 401, second differential gear 402 and outer peripheral gear 403) and a part of the drive transmission unit 200 (transmission shaft 209, force transmission member 207, first engagement member 204 and second engagement member 208).

[0098] Gear system details

[0099] like Figure 5A As shown, branch gear 302 is connected to motor 301 and rotates under the driving force of motor 301. First drive gear 303 and second drive gear 304 each engage with branch gear 302. First drive gear 303 is connected to connecting gear 201 of drive transmission unit 200, enabling drive transmission. Second drive gear 304 is connected to fourth differential gear 405 of differential mechanism section 400 via load member gear 305, enabling drive transmission. Load member gear 305 is connected to load member 306, enabling drive transmission.

[0100] Details of the drive transmission unit

[0101] The drive transmission unit 200 is a drum connector 63 connected to the box P. Figure 4The unit engages and transmits force from the device body 1A to the housing P. In this embodiment, the body-side connector 180, the first engagement member 204, and the second engagement member 208 of the drive transmission unit 200 are components that can engage with the drum connector 63 of the housing P.

[0102] like Figure 6A As shown, the body-side connector 180, the first joining member 204, the second joining member 208, the force transmission member 207, and the transmission shaft 209 are all rotating members capable of rotating around the axis M1. In this embodiment, multiple members (body-side connector 180, joining members (204 and 208)) that each engage with the driven part of the box P and transmit force to the box P are arranged concentrically.

[0103] The axis M1 can be referred to as the central axis of the drive transmission unit 200. When the drive transmission unit 200 is engaged with the drum connector 63, the drum connector 63 rotates around axis M1. Figure 4 Meanwhile, the bearing component 202 is fixed to the frame component, which is attached to the device body 1A. It should be noted that in this embodiment, with the box P attached to the device body 1A, the axis M1 coincides with the rotation axis of the photosensitive drum 61.

[0104] The direction parallel to axis M1 and along which the body-side connector 180 is positioned relative to the drum connector 63 will be referred to as the first axial direction M1A. Furthermore, the direction parallel to axis M1 and along which the drum connector 63 is positioned relative to the body-side connector 180 will be referred to as the second axial direction M1B. When the first axial direction M1A and the second axial direction M1B are not distinguished from each other, these can simply be referred to as axial directions.

[0105] like Figure 6A and Figures 8A to 8C As shown, the body-side connector 180 includes a flange portion 180a, an engagement protrusion 180b, a cylindrical portion 180c, a force transmission surface 180d, a through hole 180f, and a positioning boss 180i. The body-side connector 180 is supported by a connecting gear 201 so that it can move in a first axial direction M1A and a second axial direction M1B.

[0106] The cylindrical portion 180c is formed into a cylindrical shape centered on the axis M1. The flange portion 180a extends in a flat shape from the end portion of the cylindrical portion 180c in the first axial direction M1A. The engaging protrusion 180b protrudes further outward from the outer peripheral portion of the flange portion 180a. The engaging protrusion 180b is the portion that engages with the connecting gear 201. The force transmission surface 180d, the through hole 180f, and the locating boss 180i will be described later.

[0107] The connecting gear 201 is rotatably supported by the bearing member 202. The gear portion (tooth portion) provided on the outer peripheral portion of the connecting gear 201 engages with a gear (not shown) connected to the first drive gear 303.

[0108] The connecting gear 201 includes a mating portion 201c and an engagement surface 201d. The mating portion 201c is a wall surface portion having a generally cylindrical shape, into which the cylindrical portion 180c of the body-side connector 180 is inserted. The engagement surface 201d engages with the engagement protrusion 180b of the body-side connector 180. As a result of the contact between the engagement surface 201d and the engagement protrusion 180b, the connecting gear 201 and the body-side connector 180 rotate integrally in the normal rotation direction A1. That is, the driving force of the motor 301 is transmitted from the connecting gear 201 to the body-side connector 180 via the contact between the engagement surface 201d and the engagement protrusion 180b.

[0109] Inside the cylindrical portion 180c of the main body side connector 180, a force transmission member 207, a first engagement member 204, a second engagement member 208, a braking engagement spring 211, a connecting spring 210, and a spring retaining member 214 are provided.

[0110] Force transmission member 207 is connected to the first differential gear 401 of differential mechanism section 400 via transmission shaft 209. First engagement member 204 and second engagement member 208 are configured to engage with the second force receiving portion 63c of drum connector 63. Figure 4 The brake engagement spring 211 and the connecting spring 210 are arranged along axis M1 and generate a pushing force in the direction of axis M1 (axial direction). The spring retaining member 214 holds the brake engagement spring 211 and the connecting spring 210.

[0111] Each part disposed inside the cylindrical portion 180c of the body-side connector 180 will be further described.

[0112] like Figure 6BAs shown, the first engaging member 204 includes an annular portion 204a, a connecting engaging portion 204b, a recessed portion 204c, and a protruding portion 204e. The annular portion 204a is formed in an annular shape centered on the axis M1. The connecting engaging portion 204b is a claw-shaped protrusion from the annular portion 204a along the second axial direction M1B. The connecting engaging portion 204b is the portion that engages with the second force receiving portion 63c of the drum connector 63. In this embodiment, the connecting engaging portion 204b extends spirally toward the second axial direction M1B in a direction opposite to the normal rotation direction A1. The recessed portion 204c is a recessed shape, which is part of the end face of the annular portion 204a in the second axial direction M1B, and is recessed in the first axial direction M1A. The recessed portion 204c is the portion that engages with the protruding portion 208c of the second engaging member 208. The protruding portion 204e protrudes from the annular portion 204a in the second axial direction M1B. The protrusion 204e is the part that engages with the protrusion 207e of the force transmission member 207.

[0113] The second engaging member 208 includes an annular portion 208a, a connecting engaging portion 208b, and a protruding portion 208c. The annular portion 208a is formed in an annular shape centered on the axis M1. The connecting engaging portion 208b is a claw-shaped protrusion from the annular portion 208a along the second axial direction M1B. The connecting engaging portion 208b is the portion that engages with the second force receiving portion 63c of the drum connector 63. In this embodiment, the connecting engaging portion 208b extends spirally toward the second axial direction M1B in a direction opposite to the normal rotation direction A1.

[0114] As a result of the engagement between the protruding portion 208c and the recessed portion 204c, the relative rotation of the second engaging member 208 with respect to the first engaging member 204 is restricted. That is, the first engaging member 204 and the second engaging member 208 rotate integrally about the axis M1.

[0115] Furthermore, the first engaging member 204 is pushed against the second engaging member 208 by the pushing force of the braking engaging spring 211, so the first engaging member 204 and the second engaging member 208 also move integrally in the axial direction. Therefore, the first engaging member 204 and the second engaging member 208 can be collectively referred to as engaging members (204, 208).

[0116] It should be noted that the first joining member 204 can be referred to as the outer joining member disposed on the outer side in the radial direction, and the second joining member 208 can be referred to as the inner joining member disposed on the inner side in the radial direction. The radial direction is the radial direction of a virtual circle centered on the axis M1.

[0117] The force transmission member 207 includes a flange portion 207a, a shaft portion 207b, a hole portion 207c, an end face 207d, a protrusion 207e, and a protrusion 207f. The flange portion 207a extends radially outward from the end portion of the shaft portion 207b, which extends in the axial direction, in the second axial direction M1B. The protrusion 207e is capable of engaging with the protrusion portion 204e of the first engaging member 204.

[0118] The force transmission member 207 is configured such that the flange portion 207a is positioned in the axial direction between the annular portion 204a of the first engaging member 204 and the annular portion 208a of the second engaging member 208 (FIG. 7). The axial spacing between the annular portions 204a and 208a is greater than the thickness of the flange portion 207a, thus a gap (recoil, void) is provided between the annular portions 204a and 208a and the flange portion 207a. As a result of this gap, the force transmission member 207 is relatively movable relative to the engaging members (204, 208) in the axial direction.

[0119] Specifically, the engaging members (204, 208) can move relative to the force transmitting member 207 between an engaged position where the protrusion 207e engages with the protrusion portion 204e of the first engaging member 204 and a disengaged position where the protrusion 207e separates from the protrusion portion 204e. When the engaging members (204, 208) are in the engaged position, the force transmitting member 207 and the engaging members (204, 208) rotate integrally about axis M1. When the engaging members (204, 208) are in the disengaged position, relative rotation between the force transmitting member 207 and the engaging members (204, 208) is permitted.

[0120] When viewed in the axial direction, the bore portion 207c of the force transmission member 207 has a non-circular shape and is formed in the shaft portion 207b. The end portion of the transmission shaft 209 is inserted into the bore portion 207c (Fig. 7). As a result, the force transmission member 207 and the transmission shaft 209 rotate integrally about the axis M1. In addition, the first differential gear 401 is attached to the transmission shaft 209. Therefore, the first differential gear 401 rotates integrally with the force transmission member 207.

[0121] The braking engagement spring 211 is a helical compression spring and is in a compressed state in the axial direction between the spring retaining member 214 and the annular portion 204a of the first engagement member 204. The braking engagement spring 211 applies a repulsive force (pushing force, elastic force) to each of the spring retaining member 214 and the annular portion 204a of the first engagement member 204 in the axial direction.

[0122] The connecting spring 210 is a helical compression spring and is in a compressed state in the axial direction between the end faces 207d of the spring retaining member 214 and the force transmitting member 207 in the first axial direction M1A. The connecting spring 210 applies a repulsive force (pushing force, elastic force) to each of the spring retaining member 214 and the force transmitting member 207 in the axial direction.

[0123] The spring retaining member 214 is a tubular member disposed on the outer peripheral side of the transmission shaft 209. The repulsive force of the two springs (210, 211) causes the spring retaining member 214 to abut against the end face of the bearing member 202 in the second axial direction M1B.

[0124] The force transmission member 207 receives the repulsive force in the second axial direction M1B from the brake engagement spring 211 via the annular portion 204a of the first engagement member 204, and also receives the repulsive force in the second axial direction M1B directly from the connecting spring 210. As a result of the force in the second axial direction M1B, the protrusion 207f provided at the end portion of the force transmission member 207 along the second axial direction M1B abuts against the abutment surface 180g of the body-side connector 180 (FIG. 7).

[0125] Therefore, the body-side connector 180 is pushed in the second axial direction M1B by the repulsive force of the two springs (210, 211). A limiting member restricting the movement of the body-side connector 180 in the second axial direction M1B is provided near the body-side connector 180 (Fig. 7). The limiting member is configured to overlap with the flange portion 180a of the body-side connector 180 when viewed in the axial direction. The falling of the body-side connector 180 from the connecting gear 201 is restricted by the limiting member. The limiting member may be, for example, a member fixed to the connecting gear 201 or a member fixed to the frame of the device body 1A.

[0126] It should be noted that when the body-side connector 180 receives a force from the outside in the first axial direction M1A, the body-side connector 180 can move in the first axial direction M1A while compressing the two springs (210, 211).

[0127] like Figure 8A As shown, the body-side connector 180 includes a force transmission surface 180d. In this embodiment, the force transmission surface 180d is the surface (drive transmission surface) that transmits the force (driving force) acting in the normal rotation direction A1 when the body-side connector 180 is engaged with the drum connector 63.

[0128] The body-side connector 180 of this embodiment includes two force-transmitting surfaces 180d disposed at positions 180° apart from each other in the rotational direction about axis M1. Additionally, the body-side connector 180 of this embodiment includes two connecting engagement portions 204b disposed at positions 180° apart from each other in the rotational direction, and two connecting engagement portions 208b disposed at positions 180° apart from each other in the rotational direction. That is, when viewed in the axial direction, the shape of the end face of the body-side connector 180 on the drum connector 63 side (second axial direction M1B side) has rotational symmetry (point symmetry) about axis M1.

[0129] In the end face of the body-side connector 180 in the second axial direction M1B, a through hole 180f penetrating in the axial direction is provided in the portion other than the force transmission surface 180d. When viewed in the axial direction, the connecting and engaging portions 204b and 208b of the connecting members (204, 208) are exposed inside the through hole 180f.

[0130] Figure 8B The state of the exposed joint portions 204b and 208b of the first joint member 204 and the second joint member 208 is shown. Figure 8B The diagram shows the state in which the connecting joint portions 204b and 208b are close to each other with the force transmission surface 180d in the normal rotational direction A1 of the drum connector 63. The size of the through hole 180f is set to be greater than the width of the connecting joint portions 204b and 208b in the circumferential direction. Therefore, as... Figure 8C As shown, the connecting joint portions 204b and 208b are capable of moving within a certain range in the rotational direction within the body-side connector 180, and at this time, a gap G1 is generated between the force transmission surface 180d and the connecting joint portions 204b and 208b. When the box P is attached, the protrusion 63p of the drum connector 63 ( Figure 4 Insert into gap G1.

[0131] Details of the differential mechanism

[0132] like Figure 7B As shown, the torque limiter 410 includes an outer ring 410a and an inner ring 410b. One of the outer ring 410a and the inner ring 410b may be referred to as a first rotating member, and the other of the outer ring 410a and the inner ring 410b may be referred to as a second rotating member. In this embodiment, the outer ring 410a will be described as an example of the first rotating member, and the inner ring 410b will be described as an example of the second rotating member. The outer ring 410a will also be referred to as a housing that accommodates the inner ring 410b.

[0133] The outer ring 410a and the inner ring 410b are rotatable about axis M2, which is the same axis of rotation, and are rotatable relative to each other. Axis M2 is parallel to axis M1 of drive transmission unit 200 and passes through a position away from axis M1. That is, torque limiter 410 is provided on axis M2, which is parallel to axis M1 of body-side connector 180 and passes through a position away from axis M1. However, torque limiter 410 may be provided coaxially with body-side connector 180 on the same axis M1. According to this embodiment, for example, by providing drive transmission unit 200 to overlap with a part of differential mechanism portion 400 (e.g., differential shaft 406) when viewed in a direction orthogonal to axis M1, the space occupied by body drive system 1D in the axial direction can be reduced.

[0134] The torque limiter 410 is an example of a permissive mechanism that includes a first rotating member and a second rotating member, capable of transmitting the driving force of the motor 301 between the first and second rotating members, and configured to allow variation in the ratio between a first angular velocity of the first rotating member and a second angular velocity of the second rotating member. The permissive mechanism allows both a state where the ratio between the first and second angular velocities of the first and second rotating members is a first ratio and a state where the ratio is a second ratio different from the first ratio. It is important to note that it is sufficient for the permissive mechanism to have a configuration or function that allows variation in the ratio between the first and second angular velocities, and it is not required that the ratio between the first and second angular velocities fluctuate, for example, when the drive source (motor 301) rotates at a constant speed during image formation. Furthermore, unlike a mechanism where only two gears are coaxially arranged and the force (torque) is not transmitted between these two gears, the permissive mechanism can transmit force (torque) between the first and second rotating members.

[0135] Alternatively, the torque limiter 410 can be described as an example of a differential mechanism, which includes a first rotating member and a second rotating member and allows relative rotation (differential motion) between the first and second rotating members. The differential mechanism allows rotations with different angular velocities to be input to the first and second rotating members and absorbs the difference in angular velocity. Furthermore, the differential mechanism can transmit force (torque) between the first and second rotating members while allowing relative rotation (differential motion) between them.

[0136] The torque limiter 410 can be, for example, a dry friction plate system or a ball-ratchet system. Furthermore, the torque limiter 410 is merely an example of a permissive or differential mechanism, and different permissive or differential mechanisms can be used. For example, the permissive or differential mechanism can be the planetary gear mechanism described in the fourth embodiment. Additionally, the permissive or differential mechanism is not limited to devices that generate loads through friction, but can be a rotary damper that generates loads through the viscosity of a fluid such as oil. A rotary damper includes an inner ring (shaft) and an outer ring (housing), permisses relative rotation between the inner and outer rings, and generates a load corresponding to the speed difference between the inner and outer rings through the viscosity of the fluid sealed in the space between the inner and outer rings. As described above, the permissive or differential mechanism can be said to include a functional portion (absorbing functional portion, permissive functional portion) that absorbs the speed difference and allows changes in the speed ratio. For example, in the torque limiter 410, the contact portion between the outer ring 410a and the inner ring 410b can be said to correspond to the functional portion.

[0137] As will be described later, in printer 1 of this embodiment, when the driven portion of cartridge P is driven by motor 301 of device body 1A, the functional portion operates and allows the torque of motor 301 to be transmitted by a mechanism or differential mechanism. That is, when the driven portion of cartridge P is driven by motor 301 of device body 1A, the functional portion absorbs speed differences and allows changes in speed ratio, and the torque of motor 301 is transmitted by the allowing mechanism or differential mechanism. The time during which the driven portion of cartridge P is driven by motor 301 of device body 1A includes image formation time.

[0138] like Figure 7B As shown, a protrusion 410d is provided on the outer ring 410a, and a hole 403h is provided in the outer peripheral gear 403. As a result of the engagement between the protrusion 410d and the hole 403h, the outer ring 410a and the outer peripheral gear 403 rotate integrally about the axis M2.

[0139] like Figure 5B , Figure 5C and Figure 7B As shown, the outer peripheral gear 403 engages with the second differential gear 402. The second differential gear 402 engages with the first differential gear 401. As described above, the first differential gear 401 is attached to the transmission shaft 209. Furthermore, when the engaging members (204, 208) are in the engaged position, the transmission shaft 209 rotates integrally with the force transmission member 207 and the engaging members (204, 208). Therefore, the outer ring 410a of the torque limiter 410 is configured to rotate in a manner that is linked to the rotation of the engaging members (204, 208) of the drive transmission unit 200.

[0140] like Figure 7BAs shown, the inner ring 410b is provided with a groove portion that engages with the engagement pin 407 inserted into the differential shaft 406. As a result of the engagement between the groove portion and the engagement pin 407, the inner ring 410b rotates integrally with the differential shaft 406 about the axis M2. In addition, as a result of the engagement between the groove portion and the engagement pin 407, the torque limiter 410 is positioned in the direction of the axis M2.

[0141] The differential shaft 406 is supported by bearings 408 and 409 fixed to a frame on the device body 1A and rotates about axis M2. A third differential gear 404 is attached to the differential shaft 406. The third differential gear 404 engages with a fourth differential gear 405. The fourth differential gear 405 is connected to the drive transmission unit 200 via a connecting gear 201 (…) via the gear train 300. Figure 5A The coupling gear 201 and the body-side coupling member 180 rotate integrally in the normal rotation direction A1. Therefore, the inner ring 410b of the torque limiter 410 is configured to rotate in a manner that is linked to the rotation of the body-side coupling member 180 of the drive transmission unit 200.

[0142] The outer ring 410a and the inner ring 410b are engaged by friction. When the torque acting between the outer ring 410a and the inner ring 410b is less than a predetermined value, the outer ring 410a and the inner ring 410b rotate as a unit. When the torque acting between the outer ring 410a and the inner ring 410b is equal to or greater than the predetermined value, relative rotation between the outer ring 410a and the inner ring 410b occurs due to slippage on the friction surfaces. Therefore, the torque limiter 410 allows a difference between the angular velocity of rotation input to the outer ring 410a and the angular velocity of rotation input to the inner ring 410b.

[0143] Furthermore, the torque limiter 410 generates a load when absorbing the speed difference between the rotations input to the outer ring 410a and the inner ring 410b. That is, when there is an angular velocity difference between the outer ring 410a and the inner ring 410b, the torque in the direction of reducing the speed difference acts on each of the outer ring 410a and the inner ring 410b. In this embodiment, the load is generated by friction during the relative rotation between the outer ring 410a and the inner ring 410b (the first rotating member and the second rotating member). The load generated by the torque limiter 410 in this embodiment acts on the drum connector 63 as a braking force to limit the prior rotation of the drum connector 63 relative to the connecting gear 201. The relationship between the torque limiter 410 and the braking force will be described later.

[0144] Drum connector engagement

[0145] Reference Figure 9 and Figure 10A The engagement between the drive transmission unit 200 and the drum connector 63 in this embodiment is described. Figure 9 This is a cross-sectional view showing the drive transmission unit 200 and the drum connector 63 engaged with each other (along...). Figure 7A (The line AA is cut off). Figure 10A This is an enlarged cross-sectional view of the joint portion between the main body side connector 180, the second connecting member 208, and the drum connector 63. It should be noted that... Figure 10A Only the second engaging member 208 of the engaging members (204, 208) is shown. When the drive transmission unit 200 and the drum connector 63 are engaged, the positional relationship and force transmission direction between the first engaging member 204 and the drum connector 63 are basically the same as those of the second engaging member 208.

[0146] When the box P is attached to a predetermined position in the device body 1A, the drive transmission unit 200 and the drum connector 63 engage with each other, as shown below. Figure 9 and Figure 10A As shown. With the drive transmission unit 200 and the drum connector 63 engaged, the circular hole portion 63a of the drum connector 63 and the positioning boss 180i of the body-side connector 180 engage with each other. Figure 9 As a result of the engagement between the circular hole portion 63a and the positioning boss 180i, the rotation axis of the drum connector 63 coincides with the axis M1 of the drive transmission unit 200. That is, the drum connector 63 is adjusted (positioned).

[0147] Furthermore, with the drive transmission unit 200 and the drum connector 63 engaged, the force transmission surface 180d of the body-side connector 180 abuts against the first force receiving portion 63b of the drum connector 63. Figure 10A Furthermore, with the drive transmission unit 200 and the drum connector 63 engaged, the engagement portion 208b of the second engagement member 208 abuts against the second force receiving portion 63c of the drum connector 63. Figure 10A ).

[0148] The main body-side connector 180 rotates in the normal rotation direction A1 via drive transmission through the first drive transmission portion 1D1. With the drive transmission unit 200 and the drum connector 63 engaged, the drum connector 63 rotates in the normal rotation direction A1 because the first force receiving portion 63b is pressed by the force transmission surface 180d. That is, the force transmission surface 180d serves as a drive force application portion that applies a driving force to the drum connector 63.

[0149] Simultaneously, the second engaging member 208 is connected to the torque limiter 410 via the box-side transmission portion 1D2b of the second drive transmission portion 1D2, and transmits the load generated by the torque limiter 410 to the drum connector 63. With the drive transmission unit 200 and the drum connector 63 engaged, the drum connector 63 receives braking force in the opposite direction to the normal rotation direction A1 because the second force receiving portion 63c is pressed by the engaging portion 208b.

[0150] Therefore, the drum connector 63 rotates in the normal rotation direction A1 simultaneously with the driving force received from the body-side connector 180 while receiving braking force from the connecting members (204, 208). According to this configuration, compared to the case where the drum connector 63 does not receive braking force, the premature rotation (rapid rotation) of the drum connector 63 relative to the body-side connector 180 can be suppressed. As a result, changes in the rotational speed of the drum connector 63 and the photosensitive drum 61 can be suppressed.

[0151] The premature rotation of the drum connector 63 refers to a situation where the drum connector 63 temporarily rotates at a faster angular velocity than the body-side connector 180, and the first force receiving portion 63b separates (lifts) from the force transmission surface 180d. For example, premature rotation of the drum connector 63 may occur when an external force acts on the photosensitive drum 61 in the normal rotation direction A1. If the premature rotation of the drum connector 63 is not restricted, there is a possibility that the operation of the photosensitive drum 61 during image formation may become unstable, and the image quality may be degraded as a result. In addition, the drive speed of the drive target that is driven via the drum connector 63 can be stabilized, in addition to the photosensitive drum 61 of the cartridge P.

[0152] According to this embodiment, braking force is applied to the drum connector 63 via the connecting members (204, 208), thereby limiting the prior rotation of the drum connector 63 and suppressing changes in the rotational speed of the drum connector 63. As a result, the driving speed of the driving target such as the photosensitive drum 61 in the cartridge P can be stabilized, and for example, image quality degradation caused by changes in the rotational speed of the photosensitive drum 61 can be suppressed.

[0153] Operation of the body drive system

[0154] Reference Figure 11A , Figure 11B and Figure 12 Describe the operation and torque transmission process of the 1D drive system. Figure 11A This is a schematic diagram of the main drive system 1D when the transmission path of the drive system is not connected in a closed loop manner. Figure 11B This is a diagram showing the body drive system 1D connected in a closed loop manner. Figure 12 This is a cross-sectional unfolded view of the body drive system 1D connected in a closed loop (along... Figure 7A The diagram shows the torque transmission process in the line AA (extracted from the line).

[0155] The state in which the main drive system 1D is "connected in a closed loop manner" is, for example, composed of the first drive transmission part 1D1 and the second drive transmission part 1D2, such that force is applied in... Figure 13A The connection state is transmitted in the direction indicated by the middle arrow. The connection between the components of the main drive system 1D is, for example, the contact between the tooth surfaces of gears. When, for example, the drum connector 63 rotates constantly by the driving force of the motor 301 during the image forming operation, the main drive system 1D is connected in a closed loop manner.

[0156] like Figure 11A As shown, when there is a gap G between the tooth surfaces 402a and 403a of the second differential gear 402 and the outer peripheral gear 403, it can be said that the main drive system 1D of this embodiment is not connected in a closed loop manner. With the gap G present, torque will not be transmitted from the second differential gear 402 to the outer peripheral gear 403. For example, this occurs immediately after the motor 301 starts. Figure 11A The state.

[0157] exist Figure 11A In this state, the driving force is sequentially transmitted from the motor 301 to the branch gear 302, the first drive gear 303, the connecting gear 201, the body-side connecting member 180, and the drum connecting member 63. Furthermore, the driving force is sequentially transmitted from the drum connecting member 63 to the engaging members (204, 208), the transmission shaft 209, the first differential gear 401, and the second differential gear 402. As a result, the second differential gear 402 rotates at a circumferential speed V1. The circumferential speed V1 is the speed at which the teeth of the second differential gear 402 move along the pitch circle of the second differential gear 402. As described below, when the photosensitive drum 61 is driven constantly at a processing speed (the circumferential speed of the photosensitive drum 61 during image formation), the circumferential speed V1 can also be referred to as the circumferential speed of the second differential gear 402 and the outer peripheral gear 403. Furthermore, the circumferential speed V1 is determined by the angular velocity of the output shaft of motor 301, the speed transmission ratio of the transmission path from motor 301 to the second differential gear 402, and the pitch circle radius of the second differential gear 402. This speed transmission ratio is the ratio of the rotation angle of the second differential gear 402 to the rotation angle of the motor 301 when the second differential gear 402 is rotated by motor 301.

[0158] exist Figure 11AIn this state, the second differential gear 402 does not receive load from the torque limiter 410. Therefore, the load of the torque limiter 410 is not transmitted from the second differential gear 402 to the engagement members (204, 208) in the reverse direction through the aforementioned drive transmission path, and thus no braking force originating from the load of the torque limiter 410 is applied to the drum coupling 63. That is, in Figure 11A In this state, the advance rotation of the drum connector 63 is unrestricted.

[0159] At the same time, Figure 11A In this state, the driving force is transmitted sequentially from the motor 301 to the branch gear 302, the second drive gear 304, the load member gear 305, the fourth differential gear 405, the third differential gear 404, the differential shaft 406, the torque limiter 410, and the outer peripheral gear 403. Additionally, in Figure 11A In this state, since the outer peripheral gear 403 does not receive load from the second differential gear 402, slippage of the torque limiter 410 does not occur, and the outer peripheral gear 403 and the differential shaft 406 rotate together at an angular velocity R2. The angular velocity R2 is determined by the angular velocity of the output shaft of the motor 301 and the speed transmission ratio of the transmission path from the motor 301 to the differential shaft 406. This speed transmission ratio is the ratio of the rotation angle of the differential shaft 406 to the rotation angle of the output shaft of the motor 301 when the differential shaft 406 is rotated by the motor 301.

[0160] When the outer peripheral gear 403 rotates at an angular velocity R2 equal to the angular velocity of the differential shaft 406, the circumferential velocity of the outer peripheral gear 403 will be represented by V2. The circumferential velocity V2 is the speed at which the teeth of the outer peripheral gear 403 move along the pitch circle of the outer peripheral gear 403. The circumferential velocity V2 is expressed by multiplying the angular velocity R2 by the pitch circle radius of the outer peripheral gear 403.

[0161] Here, in Figure 11A In this state, the circumferential speed V1 of the second differential gear 402 is higher than the circumferential speed V2 of the outer gear 403 (V1 > V2). Therefore, it immediately enters the state after the motor 301 is activated. Figure 11A After that state, the teeth of the second differential gear 402 catch up with the teeth of the outer peripheral gear 403.

[0162] As a result, Figure 11B As shown, the tooth surface 402a of the second differential gear 402 contacts the tooth surface 403a of the outer peripheral gear 403. As a result of the contact between tooth surfaces 402a and 403a, torque is transmitted between the second differential gear 402 and the outer peripheral gear 403. Therefore, with tooth surfaces 402a and 403a in contact with each other, it can be said that the main drive system 1D of this embodiment is as follows: Figure 13A The connection shown is a closed loop.

[0163] When the teeth of the second differential gear 402 are as Figure 11B When the outer peripheral gear 403 catches up with the tooth of the differential gear 402, the tooth surface 403a of the outer peripheral gear 403 is pressed by the tooth surface 402a of the second differential gear 402. Therefore, the outer peripheral gear 403 rotates at a circumferential velocity V1 equal to the circumferential velocity of the second differential gear 402. At the same time, the differential shaft 406 continues to rotate at an angular velocity R2. The angular velocity R1 of the outer peripheral gear 403 corresponding to the circumferential velocity V1 is higher than the angular velocity R2 of the differential shaft 406 (R1 > R2). That is, the angular velocity R1 of the outer ring 410a, which rotates integrally with the outer peripheral gear 403, is higher than the angular velocity R2 of the inner ring 410b, which rotates integrally with the differential shaft 406.

[0164] As described above, with the main drive system 1D connected in a closed loop, different angular velocities R1 and R2 are input to the outer ring 410a and inner ring 410b of the torque limiter 410, respectively, and the torque limiter 410 slips (relative rotation between the outer ring 410a and inner ring 410b). The torque limiter 410 allows different angular velocities R1 and R2 to be input to the outer ring 410a and inner ring 410b and absorbs the difference in angular velocity.

[0165] That is, the first drive transmission portion 1D1 and the second drive transmission portion 1D2 are configured such that when the driven portion of the box P is driven by the motor 301, there is a difference between the angular velocities R1 and R2 of the outer ring 410a (first rotating member) and the inner ring 410b (second rotating member). In this embodiment, when the driven portion of the box P is driven by the motor 301 (drive source), the angular velocity R1 (first angular velocity) of the outer ring 410a (first rotating member) is higher than the angular velocity R2 (second angular velocity) of the inner ring 410b (second rotating member).

[0166] Additionally, when the outer ring 410a and the inner ring 410b rotate relative to each other, the torque limiter 410 of this embodiment generates a load to apply braking force to the drum connector 63. Specifically, in Figure 11B In this state, the outer ring 410a overcomes the friction between the outer ring 410a and the inner ring 410b and rotates at an angular velocity R1 that is higher than that of the inner ring 410b. Therefore, the outer ring 410a receives a load as frictional resistance in the direction opposite to its rotation direction. This load is transmitted from the outer peripheral gear 403 integrated with the outer ring 410a via the second differential gear 402, the first differential gear 401, and the transmission shaft 209 to the engaging members (204, 208). Then, a torque (braking force) acting in the direction opposite to the normal rotation direction A1 is transmitted from the engaging members (204, 208) to the second force receiving portion 63c of the drum connector 63. Figure 10AIn other words, when the outer ring 410a and the inner ring 410b rotate relative to each other, at least a portion of the force received by the outer ring 410a (first rotating member) from the inner ring 410b (second rotating member) is transmitted as a braking force (second force) to the driven part of the box P through the box-side transmission part 1D2b (unit-side transmission part).

[0167] As described above, with the main drive system 1D connected in a closed loop, the load generated by the torque limiter 410 inputs braking force to the drum connector 63. Therefore, the premature rotation of the drum connector 63 can be limited, and changes in the rotational speed of the drum connector 63 can be suppressed.

[0168] At the same time, Figure 11B In this state, because the inner ring 410b overcomes the friction between the inner ring 410b and the outer ring 410a and maintains an angular velocity R2 lower than that of the outer ring 410a, the inner ring 410b receives frictional force in the same direction as the rotation direction of the outer ring 410a. This frictional force can be considered part of the driving force generated by the motor 301. Furthermore, as... Figure 12 As shown, the frictional force is transmitted from the differential shaft 406, which is integral with the inner ring 410b, to the load member gear 305 via the third differential gear 404 and the fourth differential gear 405, and further from the load member gear 305 to the load member 306. Additionally, as... Figure 11B As shown, for example, the engagement surfaces between the teeth of the third differential gear 404 and the teeth of the fourth differential gear 405 are switched. That is, the fourth differential gear 405 presses against the third differential gear 404. Figure 11A ) transforms into the state where the third differential gear 404 presses down on the fourth differential gear 405. Figure 11B ).

[0169] As described above, when the main drive system 1D is connected in a closed loop, the driving force corresponding to the load generated by the torque limiter 410 is transmitted to the load member 306 via a drive transmission path extending from the motor 301 through the torque limiter 410 (see above). Figure 12 ).

[0170] In this embodiment, the load used to drive the load member 306 is greater than the driving force corresponding to the load generated by the torque limiter 410, which is transmitted to the load member 306 via the torque limiter 410 when the main drive system 1D is connected in a closed loop. Therefore, the remaining driving force required to drive the load member 306 is transmitted from the motor 301 via a path excluding the torque limiter 410 (i.e., including...). Figure 5AThe drive force is transmitted to the load member 306 via the path of the branch gear 302, the second drive gear 304, and the load member gear 305. As described above, the load member 306 in this embodiment is driven by the sum of the drive force transmitted through the path including the torque limiter 410 and the drive force transmitted through the path excluding the torque limiter 410.

[0171] Model of the body-driven system

[0172] Reference Figures 13A to 13C The torque transmission process in the body drive system 1D of this embodiment is described.

[0173] Figure 13A This is a model diagram illustrating the body driving system 1D of this embodiment. Figure 13B This is a model diagram showing the ontology driving system 1D' according to the first reference example. Figure 13B The first reference example differs from this embodiment in that the inner ring 410b of the torque limiter 410 is not connected to the motor-side transmission portion 1D2a of the second drive transmission portion 1D2, and is non-rotatably fixed to the frame 1Af of the device body 1A. That is, in this reference example, the differential shaft 406 supporting the inner ring 410b is fixed to the frame 1Af, and the third differential gear 404 and the fourth differential gear 405 are omitted. Figure 13C This is a model diagram of a body drive system 1D” of a second reference example having a configuration that further omits the torque limiter 410 from the first reference example. Other components of the body drive systems 1D' and 1D” of the first and second reference examples, as well as the box P, are the same as in this embodiment.

[0174] exist Figures 13A to 13C Torque (T) in the description L T p T TL T IF (etc.) are compared using values ​​converted to torque about the rotational axis of motor 301. Additionally, in Figures 13A to 13C In all the accompanying drawings, the load required to drive the load member 306 is represented as T. L And the load required for driving box P is represented as T. p .

[0175] First, the description Figure 13C The second reference example is shown. In the second reference example, the load received by the body-side connector 180 from the drum connector 63 will be referred to as the coupling torque T. IF In the second reference example, drum connector 63 is not connected to torque limiter 410, therefore the connection torque T IF "Equal to the load T of box P" p .

[0176] TI F = T p

[0177] In the second reference example, for example, in T p In relatively small cases, it may be easy for the photosensitive drum 61 to rotate prematurely due to external forces applied to it, or for the rotational speed of the photosensitive drum 61 to become unstable. Furthermore, the total load T acting on the motor 301 in the second reference example... M "It is the load T of box P" p and the load T of the load component 306 L sum.

[0178] T M = T p + T L

[0179] Next, in Figure 13B In the first reference example shown, due to the presence of a torque limiter 410, slippage of the torque limiter 410 occurs when driving the drive box P. Specifically, although the outer ring 410a of the torque limiter 410 rotates with an angular velocity R1 as in this embodiment, the inner ring 410b has an angular velocity of 0. Therefore, the torque limiter 410 generates a load T. TL Similar to this embodiment, the load T TL Transmission occurs from the outer ring 410a via the outer peripheral gear 403, the second differential gear 402, the first differential gear 401, and the transmission shaft 209. Then, it is transmitted to the load T. TL The corresponding braking force is input from the connecting components (204, 208) to the drum connector 63 of box P.

[0180] In the first reference example, the body-side connector 180 has a load T other than the original load T of the box P. p In addition to receiving braking force as a load input to the drum connector 63, it also rotates the drum connector 63. The load received by the body-side connector 180 from the drum connector 63 in the first reference example will be referred to as the coupling torque T. IF In the case of the first reference example, the connecting torque T IF 'Equal to the load T of box P p and the load T generated by torque limiter 410 TL sum.

[0181] T IF ' = T p + T TL

[0182] As can be seen from the equation above, due to the increased load T generated by the torque limiter 410... TLTherefore, even when T p When the torque is small, the connecting torque T acting between the body-side connector 180 and the drum connector 63 is... IF It is also unlikely to be below 0. That is, even when an external force is applied to the photosensitive drum 61, the first force receiving portion 63b of the drum connector 63 is unlikely to separate from the force transmitting surface 180d of the body-side connector 180. Therefore, in the first reference example, compared to the second reference example, the drum connector 63 is unlikely to rotate faster than the body-side connector 180, and the photosensitive drum 61 is unlikely to rotate ahead of it.

[0183] Meanwhile, the total load T acting on the motor 301 in the first reference example M 'Is the load T of box P' p The load T of load component 306 L and the load T generated by torque limiter 410 TL sum.

[0184] T M ' = T p + T L + T TL

[0185] As described above, the load T acting on the motor 301 of the first reference example M 'Greater than the load T acting on motor 301 in the second reference example M (T) M ' > T M Therefore, in the first reference example, although braking force can be applied to the drum coupling 63 through the effect of the torque limiter 410, the load acting on the motor 301 also increases the load T generated by the torque limiter 410. TL .

[0186] In contrast, Figure 13A In the main drive system 1D of this embodiment shown, the inner ring 410b of the torque limiter 410 is connected to the load member 306 via the motor-side transmission portion 1D2a of the second drive transmission portion 1D2.

[0187] Here, the load T required to drive the load member 306 L In the diagram, the portion transmitted from the motor 301 via the drive transmission path excluding the torque limiter 410 is represented as T. L ', and the portion transmitted from motor 301 through the drive transmission path including torque limiter 410 is represented as T. TL '.

[0188] In the 1D body driving system, such as Figure 11BIn the closed-loop connection state described above, the angular velocity R1 of the outer ring 410a is higher than the angular velocity R2 of the inner ring 410b, and the torque limiter 410 slips. Then, the load generated by the torque limiter 410 due to the relative rotation between the outer ring 410a and the inner ring 410b is transmitted to the load member 306 as torque (driving force) in the direction of driving the load member 306 via the motor-side transmission portion 1D2a of the second drive transmission portion 1D2. The load T transmitted through the drive transmission path including the torque limiter 410... TL The load is generated by the torque limiter 410 due to the relative rotation between the outer ring 410a and the inner ring 410b. That is, when the outer ring 410a (first rotating member) and the inner ring 410b (second rotating member) rotate relative to each other, at least a portion of the force received by the inner ring 410b (second rotating member) from the outer ring 410a (first rotating member) is transmitted to the load member via the motor-side transmission portion 1D2a (drive source-side transmission portion). Load T TL It can also be referred to as the driving force transmitted from the motor 301 through the driven part including the box P and the torque limiter 410 to the load member 306.

[0189] The driving force (T) applied from the torque limiter 410 to the load member 306 TL ') can be a load (T) corresponding to the braking force input from the torque limiter 410 via the box-side transmission section 1D2b to the drum connector 63. TL The smaller value. This is because although the load (friction) received by the outer ring 410a and the load (friction) received by the inner ring 410b are torques of the same magnitude but opposite in direction about the rotation axis of the torque limiter 410, T TL 'and T TL It is a value converted to torque about the rotation axis of motor 301.

[0190] Here, the load T is used to drive the load member 306. L Greater than the driving force (T) applied from the torque limiter 410 to the load member 306 TL ').

[0191] T TL ' < T L

[0192] Therefore, the driving force transmitted from the motor 301 to the load member 306 through the drive transmission path excluding the torque limiter 410 and the driving force (T) applied to the load member 306 from the torque limiter 410 are both transmitted through the drive transmission path. TL Both drive the load component 306. That is, T L T TL 'and T LIt is in the following relationship.

[0193] T L ' = T L - T TL

[0194] Similarly, in this embodiment, the torque limiter 410 slips when the drive box P is activated. Specifically, although the outer ring 410a of the torque limiter 410 rotates at an angular velocity R1, the inner ring 410b rotates at an angular velocity R2, which is lower than that of the outer ring 410a. Therefore, the torque limiter 410 generates a load T. TL The load T TL Transmission occurs from the outer ring 410a via the outer peripheral gear 403, the second differential gear 402, the first differential gear 401, and the transmission shaft 209. Then, it is transmitted to the load T. TL The corresponding braking force is input from the connecting components (204, 208) to the drum connector 63 of box P.

[0195] Similarly, in this embodiment, as in the first reference example, the body-side connector 180 has a load T other than the original load T of the box P. p In addition to receiving braking force as a load input to the drum connector 63, it also rotates the drum connector 63. The load received by the body-side connector 180 from the drum connector 63 in this embodiment will be referred to as the connecting torque T. IF Connection torque T IF This is the torque acting between the body-side connecting member 180 and the drum connecting member 63. In the case of the first embodiment, the connecting torque T IF The load T equals that of box P p and the load T generated by torque limiter 410 TL sum.

[0196] T IF = T p + T TL

[0197] As can be seen from the above formula, similarly in this embodiment and the reference example, the load generated by the torque limiter 410 makes it unlikely that the drum connector 63 will rotate ahead of the body-side connector 180.

[0198] Furthermore, the total load T acting on the motor 301 in this embodiment M The load T of box P p The load T generated by the torque limiter 410 TL and the load T of the load component 306 L Part of (T) L The sum of '). The load T of load member 306. L Part of (T)L ') is the load T required to drive the load member 306. L The load T transmitted from motor 301 through a drive transmission path excluding torque limiter 410. That is, the load T acting on motor 301 during image formation. M It can be represented as follows.

[0199] T M = T p + T TL + T L '

[0200] As mentioned above, due to T L ' = T L - T TL Since the relationship holds, the above equation can be rewritten as follows.

[0201] T M = T p + T TL + T L - T TL '

[0202] = Tp + T L + (T TL - T TL ')

[0203] By applying the above equation to the load T acting on the motor 301 of the first reference example M By comparing the equations, it can be seen that the load T acting on the motor 301 in this embodiment... M The driving force (T) transmitted to the load member 306 via the torque limiter 410 is reduced. TL The quantity corresponding to ').

[0204] Advantages of this embodiment

[0205] As described above, according to this embodiment, an image forming apparatus including new elements related to the driving of the replaceable unit can be provided.

[0206] For example, according to this embodiment, the driving force in the normal rotation direction A1 and the braking force in the opposite direction can be transmitted to the drum connector 63 of the housing P via a closed-loop transmission path. As a result, the premature rotation of the drum connector 63 and the photosensitive drum 61 can be suppressed, and the housing P can be driven at a more stable driving speed. Specifically, in this embodiment, the above advantages can be obtained by a configuration in which the load generated by the torque limiter 410 (allowing mechanism, differential mechanism) is transmitted as a braking force in the direction opposite to the normal rotation direction A1 to the drum connector 63.

[0207] Furthermore, according to this embodiment, the load member 306 is driven by the load generated by the torque limiter 410, thus reducing the load acting on the motor 301. Therefore, the lifespan of the motor 301 can be extended, the heat generated by the motor 301 can be reduced, and the energy efficiency of the motor 301 can be improved. Additionally, since a small or low-output motor 301 can be used, for example, this configuration facilitates device miniaturization or cost reduction.

[0208] The improvement in energy efficiency by reducing the load on motor 301 can also be explained from the perspective of energy consumption (dissipation) of torque limiter 410. That is, the load generated by torque limiter 410 (torque value of torque limiter 410) is the same between the first reference example and the first embodiment. However, in the first reference example, all the mechanical work (torque value × R1) required to rotate the outer ring 410a of torque limiter 410 at an angular velocity R1 to overcome the frictional resistance between the outer ring 410a and the inner ring 410b is dissipated as heat. In contrast, in the first embodiment, since the speed difference (R1-R2) between the outer ring 410a and the inner ring 410b is smaller than that in the first reference example, the mechanical work (torque value × (R1-R2)) required to rotate the outer ring 410a to overcome the frictional resistance between the outer ring 410a and the inner ring 410b is smaller than that in the first reference example. Therefore, even with the same load generated by the torque limiter 410, the mechanical energy dissipated (heated) by the torque limiter 410 in the first embodiment is less than that in the first reference example. As a result, the energy efficiency (the ratio of mechanical work to the power consumption of the motor 301) of the overall body drive system 1D can be improved, thereby enhancing energy saving.

[0209] In addition, in this embodiment, since the speed difference between the outer ring 410a and the inner ring 410b of the torque limiter 410 is smaller than that in the first reference example, the wear of the torque limiter 410 can be reduced, thereby extending the life of the torque limiter 410.

[0210] Modify Example

[0211] In this embodiment, the configuration in which the load member 306 is connected to a part of the main drive system 1D (the motor-side transmission portion 1D2a of the second drive transmission portion 1D2) has been described. However, the main drive system 1D does not need to be connected to load members other than the housing P. In addition, different load members other than the load member 306 can be connected to other parts of the main drive system 1D (e.g., the first drive transmission portion 1D1).

[0212] Additionally, the force transmission direction in the first drive transmission section 1D1 and the second drive transmission section 1D2 can be modified according to the specific configuration of the printer 1 (see also the second and third embodiments).

[0213] Furthermore, although this embodiment uses a configuration without a cleaning portion that contacts the photosensitive drum 61, the housing P may include a cleaning portion. The cleaning portion is, for example, a scraper member that rubs against the photosensitive drum 61. When the load applied to the photosensitive drum 61 by the cleaning portion is relatively small, premature rotation of the drum connector 63 may occur. According to the configuration in this embodiment, where a braking force is applied to the drum connector 63 by the load generated by the torque limiter 410, premature rotation of the drum connector 63 can be suppressed even when the load applied to the photosensitive drum 61 by the cleaning portion is relatively small.

[0214] Furthermore, although the branch gear 302 is described as an example of an output section in this embodiment, it is acceptable as long as the output section is configured to form part of a closed-loop transmission path and is capable of outputting the driving force of the drive source. For example, in this embodiment, when the first drive gear 303 and the second drive gear 304 each engage with a pinion on the output shaft of the motor 301, the pinion serves as the output section.

[0215] Furthermore, although the load T of the load member 306 has been described in this embodiment, L The load T generated by the torque limiter 410 is greater than the load T generated by the torque limiter 410. TL In this case, however, the magnitude relationship between the two loads can be reversed. That is, the load T of load member 306... L It can be equal to or less than the load T generated by the torque limiter 410. TL (T) L ≤ T TL ).

[0216] Second Embodiment

[0217] Reference Figures 14A to 17D Another embodiment of this disclosure (the second embodiment) is described below. In the following description, unless otherwise stated, it is assumed that elements indicated by the same reference numerals as those in the first embodiment have substantially the same configuration and function as those described in the first embodiment, and the parts that differ from the first embodiment will be described primarily.

[0218] In the first embodiment, an example has been described whereby the driving force is sequentially transmitted from the connecting gear 201 to the body-side connecting member 180, the drum connecting member 63, and the first differential gear 401. Figure 12 In this embodiment, an example will be described whereby the driving force is sequentially transmitted to the first differential gear 401, the drum connector 63, the body-side connector 180, and the connecting gear 201. Figure 15 ).

[0219] In addition to the fact that the driving force is transmitted in the aforementioned transmission direction, the drive transmission unit 200 and drum connector 63 in this embodiment have a mirror-symmetrical structure relative to the drive transmission unit 200 and drum connector 63 in the first embodiment. That is, when viewed along the axis M1, the shape of the drive transmission unit 200 in this embodiment can be the same as the shape obtained by flipping the view of the drive transmission unit 200 in the first embodiment along the axis M1. Similarly, when viewed along the axis M1, the shape of the drum connector 63 in this embodiment can be the same as the shape obtained by flipping the view of the drum connector 63 in the first embodiment along the axis M1.

[0220] Specifically, in this embodiment, the positional relationship between the force transmission surface 180d of the body-side connector 180, the connecting and engaging portion 208b of the second engaging member 208, and the first force receiving portion 63b and the second force receiving portion 63c of the drum connector 63 is as follows: Figure 10B As shown. The direction of rotation of the drum connector 63 during image formation is referred to as the normal rotation direction A1. In this case, in the first embodiment, the force transmission surface 180d, the first force receiving portion 63b, the second force receiving portion 63c, and the connecting engagement portion 208b are arranged sequentially from the upstream side to the downstream side of the normal rotation direction A1. Figure 10A In contrast, in this embodiment ( Figure 10B The connecting joint portion 208b, the second force receiving portion 63c, the first force receiving portion 63b, and the force transmission surface 180d are arranged sequentially from the upstream side to the downstream side in the normal rotation direction A1.

[0221] Operation of the body drive system

[0222] Reference Figure 14A and Figure 14B The operation and torque transmission process of the body drive system 1D according to the second embodiment are described. Figure 14A This is a schematic diagram of the main drive system 1D when the transmission path of the drive system is not connected in a closed loop manner. Figure 14B This is a diagram showing the body drive system 1D connected in a closed loop manner. Figure 15 This is a diagram showing the torque transmission flow in a cross-sectional unfolded view of the main drive system 1D connected in a closed loop.

[0223] like Figure 14AAs shown, when there is a gap G between the tooth surfaces 402b and 403b of the second differential gear 402 and the outer peripheral gear 403, it can be said that the main drive system 1D of this embodiment is not connected in a closed loop manner. With the gap G present, torque will not be transmitted from the outer peripheral gear 403 to the second differential gear 402. For example, this occurs immediately after the motor 301 starts. Figure 14A The state.

[0224] exist Figure 14A In this state, the driving force is sequentially transmitted from the motor 301 to the branch gear 302, the first drive gear 303, the connecting gear 201, and the body-side connecting member 180, and the body-side connecting member 180 rotates along the normal rotation direction A1. The normal rotation direction A1 is the direction in which the force transmission surface 180d of the body-side connecting member 180 moves away from the first force receiving portion 63b of the drum connecting member 63 (see [reference]). Figure 10B Additionally, as described below, in Figure 14A In this state, torque will not be transmitted from torque limiter 410 to drum connector 63. Therefore, immediately after motor 301 starts... Figure 14A In this state, the drum connector 63 remains stationary and does not rotate in the normal rotation direction A1.

[0225] At the same time, Figure 14A In this state, the driving force is transmitted from the motor 301 to the branch gear 302, the second drive gear 304, the load member gear 305, the fourth differential gear 405, the third differential gear 404, and the differential shaft 406, and the differential shaft 406 rotates at an angular velocity R4. Figure 14A In this state, since the outer peripheral gear 403 does not receive load from the second differential gear 402, slippage of the torque limiter 410 does not occur, and the outer peripheral gear 403 and the differential shaft 406 rotate together at an angular velocity R4. The angular velocity R4 is determined by the angular velocity of the output shaft of the motor 301 and the speed transmission ratio of the transmission path from the motor 301 to the differential shaft 406. This speed transmission ratio is the ratio of the rotation angle of the differential shaft 406 to the rotation angle of the output shaft of the motor 301 when the differential shaft 406 is rotated by the motor 301.

[0226] When the outer peripheral gear 403 rotates at an angular velocity R4 equal to the angular velocity of the differential shaft 406, the circumferential velocity of the outer peripheral gear 403 will be represented by V4. The circumferential velocity V4 is the speed at which the teeth of the outer peripheral gear 403 move along its pitch circle. The circumferential velocity V4 is expressed by multiplying the angular velocity R4 by the pitch circle radius of the outer peripheral gear 403.

[0227] exist Figure 14AIn this state, when the outer peripheral gear 403 rotates at a circumferential speed V4, the second differential gear 402 remains stationary and does not rotate due to the clearance G. Furthermore, the first differential gear 401, the transmission shaft 209, and the engaging members (204, 208) also remain stationary and do not rotate. Therefore, the torque in the normal rotation direction A1 is not transmitted from the engaging members (204, 208) to the drum connector 63. Consequently, the drum connector 63 remains stationary and does not rotate in the normal rotation direction A1.

[0228] When in Figure 14A In a state that lasts for a very short time, such as Figure 14B As shown, the tooth surface 403b of the outer peripheral gear 403 and the tooth surface 402b of the second differential gear 402 are in contact with each other, and the second differential gear 402 begins to rotate at a circumferential speed V4. With tooth surfaces 402b and 403b in contact, it can be said that the main drive system 1D of this embodiment is as follows: Figure 16 The connection shown is a closed loop.

[0229] As the second differential gear 402 rotates, the first differential gear 401, the transmission shaft 209, and the engaging members (204, 208) also begin to rotate. Then, the torque (driving force) in the normal rotation direction A1 is transmitted from the engaging members (204, 208) to the drum connector 63.

[0230] Here, the angular velocity of the engaging members (204, 208) corresponding to the circumferential velocity V4 of the second differential gear 402 is higher than that of the engagement members (204, 208). Figure 14A The angular velocities of the body-side connector 180 and the drum connector 63 in the specified state. However, the body-side connector 180 is connected to the first drive gear 303 via the connecting gear 201, and the angular velocity of the first drive gear 303 is limited by its engagement with the branch gear 302. Even if the second differential gear 402 starts to rotate at a circumferential speed V4 and the branch gear 302 starts to be pressed by the first drive gear 303, the angular velocity of the branch gear 302 will not change. This is because the force of the first drive gear 303 pressing the branch gear 302 is a portion of the force output from the branch gear 302 to the second drive gear 304, which returns to the branch gear 302 via a closed-loop transmission path. That is, a portion of the force of the branch gear 302 pressing the second drive gear 304 against a load exceeding the transmission path of the second drive gear 304 (including the first drive gear 303) returns from the first drive gear 303 to the branch gear 302. Therefore, the force of the first drive gear 303 pressing the branch gear 302 does not exceed the load used to rotate the second drive gear 304, and thus the angular velocity of the branch gear 302 does not increase.

[0231] Therefore, after the rotation of the second differential gear 402 begins, the second differential gear 402 temporarily rotates at a circumferential speed V4 equal to the circumferential speed of the outer peripheral gear 403, and then decelerates to a circumferential speed V3 (V4 > V3) lower than the circumferential speed V4. The circumferential speed V3 is the circumferential speed of the second differential gear 402 when the drum connecting member 63 and the engaging members (204, 208) rotate at the same angular velocity as the body-side connecting member 180.

[0232] like Figure 14B As shown, as a result of the reduction in speed by the second differential gear 402, the outer peripheral gear 403 also reduces its speed from circumferential velocity V4 to circumferential velocity V3. In contrast, the differential shaft 406 continues to decelerate at a speed similar to... Figure 14A The outer ring 403, which rotates with the same angular velocity R4 as the outer ring 403, has a lower angular velocity R3 than the differential shaft 406 (R4 > R3). In other words, the outer ring 410a of the torque limiter 410, which rotates integrally with the outer ring 403, has a lower angular velocity R3 than the inner ring 410b of the torque limiter 410, which rotates integrally with the differential shaft 406.

[0233] As described above, with the main drive system 1D connected in a closed loop, different angular velocities R3 and R4 are input to the outer ring 410a and inner ring 410b of the torque limiter 410, respectively, and the torque limiter 410 slips (relative rotation between the outer ring 410a and inner ring 410b). That is, in this embodiment, the torque limiter 410, which serves as a permissive mechanism or differential mechanism, allows different angular velocities R3 and R4 to be input to the outer ring 410a (first rotating member) and inner ring 410b (second rotating member), and absorbs the difference in angular velocity.

[0234] That is, the first drive transmission portion 1D1 and the second drive transmission portion 1D2 are configured such that when the driven portion of the box P is driven by the motor 301, there is a difference between the angular velocities R3 and R4 of the outer ring 410a (first rotating member) and the inner ring 410b (second rotating member). In this embodiment, when the driven portion of the box P is driven by the motor 301, the angular velocity R3 (first angular velocity) of the outer ring 410a (first rotating member) is higher than the angular velocity R4 (second angular velocity) of the inner ring 410b (second rotating member).

[0235] In addition, Figure 14B and Figure 15In the current state, when the drum connector 63 receives a force (driving force, third force) in the normal rotation direction A1 from the connecting members (204, 208), the drum connector 63 also receives a force (braking force, fourth force) in the opposite direction to the normal rotation direction A1 from the body-side connector 180. That is, during image formation, the force (braking force, fourth force) received by the first force receiving portion 63b from the first drive transmission portion 1D1 of the body drive system 1D acts on the drum connector 63 in the direction opposite to the normal rotation direction A1 (second rotation direction). During image formation, the force (driving force, third force) received by the second force receiving portion 63c from the second drive transmission portion 1D2 of the body drive system 1D acts on the drum connector 63 in the normal rotation direction A1 (first rotation direction). That is, the box P (replaceable unit) in this embodiment includes a second force receiving portion 63c (third surface) that receives driving force (third force) from the second drive transmission portion 1D2 and a first force receiving portion 63b (fourth surface) that receives braking force (fourth force) from the first drive transmission portion 1D1.

[0236] Therefore, similar to the first embodiment, the premature rotation of the drum connector 63 can be suppressed, and the box P can be driven at a stable driving speed.

[0237] Incidentally, in Figure 14B and Figure 15 In this state, the drum connector 63 presses against the body-side connector 180 in the normal rotation direction A1 while rotating, and the speed of the body-side connector 180 is limited by the rotation of the branch gear 302. That is, a portion of the force (driving force) of the engaging members (204, 208) pressing against the drum connector 63 in the normal rotation direction A1 is transmitted from the drum connector 63 to the body-side connector 180. The magnitude of this force corresponds to the value obtained by subtracting the load required by the drive box P from the load generated by the torque limiter 410.

[0238] In addition, Figure 14B and Figure 15 In the current state, the force transmitted from the drum connector 63 to the body-side connector 180 is transmitted from the body-side connector 180 to the branch gear 302 via the connecting gear 201 and the first drive gear 303. In other words, a portion of the braking force (third force) applied to the driven portion of the box P from the second drive transmission section 1D2 is transmitted from the driven portion to the branch gear 302 (output portion) via the first drive transmission section 1D1.

[0239] The direction of the force (torque) transmitted from the driven part of box P to the branch gear 302 (output part) via the first drive transmission part 1D1 is the same as the direction of rotation of the branch gear 302 when the driven part of box P is driven by the driving force of motor 301 (drive source). That is, the force transmitted from the driven part of box P to the branch gear 302 (output part) via the first drive transmission part 1D1 can assist the rotation of the branch gear 302 (output part).

[0240] Model of the body-driven system

[0241] Reference Figure 16 The process of torque transmission in the body drive system 1D of the second embodiment is described. Figure 16 This is a model diagram illustrating the 1D body driving system of this embodiment. Figure 16 The torques used in the description are compared by using values ​​converted to torque acting on the output shaft of motor 301.

[0242] like Figure 16 As shown, the torque transmitted from motor 301 to the inner ring 410b of torque limiter 410 via motor-side transmission portion 1D2a of second drive transmission portion 1D2 will be expressed as T. TL2 The torque transmitted from the outer ring 410a of the torque limiter 410 to the drum connector 63 of the housing P via the housing-side transmission portion 1D2b of the second drive transmission portion 1D2 will be expressed as T. TL2 '.

[0243] As described above, since the angular velocity R3 of the outer ring 410a is lower than the angular velocity R4 of the inner ring 410b during image formation (R4 > R3), slippage (relative rotation) occurs between the outer ring 410a and the inner ring 410b during image formation. Torque T TL2 The torque required to overcome the friction between the outer ring 410a and the inner ring 410b, causing the inner ring 410b to rotate relative to the outer ring 410a. Torque T TL2 This corresponds to the torque applied to the outer ring 410a by the friction between the outer ring 410a and the inner ring 410b. In this embodiment, when comparing torque values ​​about the rotation axis of the motor 301, the torque value is at T. TL2 ' < T TL2 The relationship.

[0244] Similarly, in this embodiment, as in the first embodiment, the drum connector 63 receives torque (driving force, first force) from the body drive system 1D along the normal rotation direction A1, and also receives torque (braking force, second force) from the body drive system 1D in the opposite direction to the normal rotation direction A1. However, unlike the first embodiment, the drum connector 63 receives driving force from the engaging members (204, 208) of the second drive transmission portion 1D2, and receives braking force from the body-side connector 180 of the first drive transmission portion 1D1 (see also...). Figure 10B ).

[0245] The force received by the body-side connector 180 from the drum connector 63 in this embodiment will be referred to as the connecting torque T. IF2 Additionally, the load required by the drive box P will be represented as T. p As described above, the drum connector 63 receives torque T from the torque limiter 410 via the box-side transmission portion 1D2b of the second drive transmission portion 1D2. TL2 Overcoming the load T of box P p It rotates in the normal rotation direction A1. As a result of the drum connector 63 pressing the body-side connector 180 in the normal rotation direction A1, the torque received by the body-side connector 180 is equal to the torque T from the input to the drum connector 63. TL2 'Subtract the load T of box P p The obtained value. That is, the connection torque T in this embodiment. IF2 The value of can be expressed by the following equation.

[0246] T IF2 = T TL2 ' - T p

[0247] As can be seen from the above equation, if the torque T transmitted from the torque limiter 410 to the drum connector 63... TL2 'If it is large, then even if the load T of box P is large...' p Temporarily increase, connecting torque T IF2 It will not fall below 0. For example, considering the load T during the normal image forming operation of printer 1. p The range of variation is used to set the torque value of the torque limiter 410, so that for T p The expected upper limit, the connecting torque T IF2 Negative values ​​are not taken. As a result, the load T in box P... p In the case of a temporary increase, it is also possible to suppress the situation where the rotation speed of the drum connector 63 changes, causing the rotation of the drum connector 63 to be delayed relative to the rotation of the body-side connector 180.

[0248] Furthermore, according to the above equation, it can be seen that the load T on box P is... pIn the case of a temporary reduction, the connecting torque T IF2 The size increases, making it unlikely that the drum connector 63 and the body-side connector 180 will separate from each other. This will be referred to later. Figures 17A to 17D Describe it.

[0249] In this embodiment, the connection torque T input from the drum connector 63 to the body-side connector 180 is... IF2 It returns to the branch gear 302 via the first drive transmission section 1D1. Connecting torque T IF2 The direction acting on the branch gear 302 (the direction of rotation about the axis of rotation of the branch gear 302) is the same as the direction of rotation of the branch gear 302 during image formation. Therefore, the coupling torque T returning to the branch gear 302... IF2 The auxiliary branch gear 302 rotates during image formation.

[0250] Specifically, the load required to drive the load component 306 will be expressed as T. L Additionally, the sum of the loads acting on motor 301 during image formation will be expressed as T. M2 Motor 301 overcomes load T L Drive load member 306 to overcome torque T corresponding to the slip resistance of torque limiter 410 TL2 This causes the outer ring 410a of the torque limiter 410 to rotate. Simultaneously, the connecting torque T returns to the branch gear 302 via the first drive transmission section 1D1. IF2 The outer ring 410a is used to rotatably drive the load member 306 and the torque limiter 410. That is, in this embodiment, the load T acting on the motor 301 during image formation... M2 It can be represented as follows:

[0251] T M2 = T L + T TL2 - T IF2

[0252] = T L + T TL2 - (T TL2 ' - T p )

[0253] = T p + T L + (T TL2 - T TL2 ')

[0254] As a first reference example of the first embodiment ( Figure 13BAs described, in the configuration where the inner ring 410b of the torque limiter 410 is fixed, the load T acting on the motor 301 during image formation... M2 'Equal to box P of T p The load T of load component 306 L and the torque T corresponding to the slip resistance of the torque limiter 410 TL2 The sum of (T) M2 ' = T p + T L + T TL2 ).

[0255] T M2 With T M2 By comparison, it can be seen that, according to this embodiment, the load on the motor 301 can be reduced compared to the torque T transmitted from the torque limiter 410 to the drum connector 63 via the box-side transmission portion 1D2b of the second drive transmission portion 1D2. TL2 'Corresponding quantity'.

[0256] Suppression of the leading rotation of the photosensitive drum

[0257] Reference Figures 17A to 17D Compared with the second reference example above ( Figure 13C The behavior of the body drive system 1D is described by comparison when an external force is applied to the photosensitive drum 61 in the normal rotation direction A1. Figures 17A to 17D The image shows the photosensitive drum 61, belt 41, and a portion of the body drive system 1D (connecting gear 201 and upstream gear 190) as viewed along the axis of rotation of the photosensitive drum 61. Figure 17A This illustrates how the drive is passed during normal image formation in this embodiment. Figure 17B This illustrates the case where the force transmitted from the belt 41 to the photosensitive drum 61 along the normal rotational direction A1 increases in this embodiment. Figure 17C The second reference example illustrates how the drive is passed during normal image formation. Figure 17D The second reference example shows an increase in the force transmitted from the belt 41 to the photosensitive drum 61 in the normal rotational direction A1.

[0258] like Figure 17AAs shown, the gear that is part of the first drive transmission section 1D1 and engages with the connecting gear 201 will be referred to as the upstream gear 190. In this embodiment, when the drum connector 63 receives a force (driving force) along the normal rotation direction A1 from the engaging members (204, 208), the drum connector 63 receives a force (braking force) in the opposite direction to the normal rotation direction A1 from the body-side connector 180. Therefore, during normal image formation, the body-side connector 180 is rotated by being pressed by the drum connector 63 along the normal rotation direction A1. In addition, the connecting gear 201, which rotates integrally with the body-side connector 180, rotates along the normal rotation direction A1 while pressing the upstream gear 190.

[0259] That is, in this embodiment, during normal image formation, the tooth surface 201a of the downstream side of the connecting gear 201 in the normal rotation direction A1 abuts against the tooth surface 190a of the corresponding upstream gear 190. That is, when the driven part of the cartridge P is driven by the motor 301 (drive source), the tooth surface 201a (first tooth surface) of the connecting gear 201 (first gear) abuts against the tooth surface 190a (second tooth surface) of the upstream gear 190 (second gear).

[0260] In contrast, Figure 17C In the second reference example shown, the drum connector 63 receives a force (driving force) along the normal rotation direction A1 from the body-side connector 180. Therefore, during normal image formation, the connecting gear 201 rotates along the normal rotation direction A1 by being pressed by the upstream gear 190. Additionally, the body-side connector 180, which rotates integrally with the connecting gear 201, rotates along the normal rotation direction A1 while pressing the drum connector 63.

[0261] That is, in the case of the second reference example, during normal image formation, the tooth surface 201b of the upstream side of the connecting gear 201 in the normal rotation direction A1 abuts against the tooth surface 190b of the corresponding upstream gear 190.

[0262] Here, in this embodiment and the second reference example, the circumferential speed of the belt 41 during image formation is set to be higher than the circumferential speed of the photosensitive drum 61. Therefore, the photosensitive drum 61 receives a prior rotational force Fb from the belt 41 as a force along the normal rotation direction A1.

[0263] In the second reference example, the body-side connector 180 receives a force from the drum connector 63, including the rotational load of the photosensitive drum 61 and a prior rotational force Fb. When the prior rotational force Fb is less than the rotational load of the photosensitive drum 61, the photosensitive drum 61 and the drum connector 63 do not rotate at an angular velocity higher than the angular velocity of the body-side connector 180, and the photosensitive drum 61 rotates at a stable speed.

[0264] However, the value of the leading rotational force Fb can be changed, for example, by an impact that occurs when the front end of the sheet contacts the belt 41 or when the rear end of the sheet is released from the belt 41. When the leading rotational force Fb is temporarily greater than the rotational load of the photosensitive drum 61, the photosensitive drum 61 and the drum coupling 63 rotate at an angular velocity higher than the angular velocity of the body-side coupling 180 (leading rotation). Then, as... Figure 17D As shown, the engagement surfaces between the connecting gear 201 and the upstream gear 190 switch from tooth surfaces 190b and 201b to tooth surfaces 190a and 201a.

[0265] Then, when from Figure 17C The state transition to Figure 17D In this state, neither the tooth surfaces 201a nor 201b of the connecting gear 201 are in contact with the tooth surfaces 190a or 190b of the upstream gear 190. That is, in the second reference example, depending on the magnitude of the external force (Fb) applied to the normal rotation direction A1 of the photosensitive drum 61, the rotation of the photosensitive drum 61 may be unstable due to the temporary disconnection of the connection between the upstream gear 190 and the connecting gear 201.

[0266] It should be noted that, according to the first reference example ( Figure 13B The drum connector 63 receives a force (braking force) from the engaging members (204, 208) in the opposite direction to the normal rotation direction A1. Therefore, compared to the second reference example, it is unlikely that the drum connector 63 will rotate prematurely. However, also in the first reference example, premature rotation of the drum connector 63 may occur if the premature rotational force Fb applied to the photosensitive drum 61 exceeds the sum of the rotational load on the photosensitive drum 61 and the braking force from the engaging members (204, 208).

[0267] In contrast, according to Figure 17A In the configuration of this embodiment shown, even during normal image formation, the tooth surface 201a of the downstream side of the connecting gear 201 in the normal rotation direction A1 is in contact with the tooth surface 190a of the upstream gear 190. Therefore, even if the prior rotational force Fb applied to the photosensitive drum 61 temporarily increases, it is only an increase in the force acting between tooth surfaces 190a and 201a, and the mating surfaces do not switch from tooth surfaces 190a and 201a to tooth surfaces 190b and 201b. Conversely, as shown in the above equation (T... IF2 = T TL2 ' - T p As can be seen, when the load T of box P... p When the initial rotational force Fb decreases, the connecting torque (T) acting between the body-side connector 180 and the drum connector 63 is... IF2 )Increase.

[0268] In other words, suppose an external force is applied that causes the drum connector 63 to rotate in the normal rotation direction A1 (first rotation direction) at a speed higher than the driving speed of the drum connector 63 (rotating member) driven by the motor 301 (drive source). In this case, the first drive transmission portion 1D1 is configured such that the tooth surface 201a (first tooth surface) of the tooth of the connecting gear 201 (first gear) and the tooth surface 190a (second tooth surface) of the tooth of the upstream gear 190 (second gear) are in contact. Furthermore, in this case, the first drive transmission portion 1D1 is configured such that the force (T) acting between the fourth surface of the housing P (first force receiving portion 63b) and the first drive transmission portion 1D1... IF2 It increases according to external forces.

[0269] Therefore, according to the configuration of this embodiment, even if the prior rotational force Fb applied to the photosensitive drum 61 temporarily increases, the prior rotation of the photosensitive drum 61 and the drum connector 63 can be suppressed, and the rotational speed of the photosensitive drum 61 can be stabilized.

[0270] It should be noted that although it has been described that the circumferential speed of the belt 41 during image formation is set to be higher than that of the photosensitive drum 61, there are also cases where the photosensitive drum 61 receives external forces in the normal rotation direction A1 for other reasons. For example, in the case of a direct transfer system that transfers the toner image directly from the photosensitive drum 61 to the sheet S instead of via the belt 41 (intermediate transfer member), the photosensitive drum 61 may receive a prior rotational force Fb from the sheet S. In the same case, according to this embodiment, the prior rotation of the photosensitive drum 61 and the drum connector 63 can be suppressed, and the rotational speed of the photosensitive drum 61 can be made more stable.

[0271] Advantages of this embodiment

[0272] As described above, according to this embodiment, an image forming apparatus including new elements related to the driving of the replaceable unit can be provided.

[0273] For example, according to this embodiment, the driving force in the normal rotation direction A1 and the braking force in the opposite direction can be transmitted to the drum connector 63 of the housing P via a closed-loop transmission path. As a result, the premature rotation of the drum connector 63 and the photosensitive drum 61 can be suppressed, and the housing P can be driven at a more stable driving speed. Specifically, in this embodiment, the above advantages can be achieved by a configuration in which the load generated by the torque limiter 410 (allowing mechanism, differential mechanism) is transmitted as a force (driving force) in the normal rotation direction A1 to the drum connector 63.

[0274] Furthermore, according to this embodiment, a portion of the load generated by the torque limiter 410 is returned to the branch gear 302 (output section) through a closed-loop transmission path, thus reducing the load acting on the motor 301. Therefore, the lifespan of the motor 301 can be extended, the heat generated by the motor 301 can be reduced, and the energy efficiency of the motor 301 can be improved. Additionally, since a small or low-output motor 301 can be used, for example, this configuration facilitates equipment miniaturization or cost reduction.

[0275] Furthermore, according to this embodiment, as referenced Figures 17A to 17D As described above, even if the prior rotational force Fb applied to the photosensitive drum 61 suddenly increases, the change in the rotational speed of the photosensitive drum 61 can be suppressed.

[0276] Third Embodiment

[0277] Reference Figures 18A to 20 Another embodiment of this disclosure (a third embodiment) is described below. In the following description, unless otherwise stated, it is assumed that elements indicated by the same reference numerals as those in the first embodiment have substantially the same configuration and function as those described in the first embodiment, and the parts that differ from the first embodiment will be described primarily.

[0278] Operation of the body drive system

[0279] Reference Figure 18A , Figure 18B and Figure 19 Describe the operation and torque transmission process of the 1D drive system. Figure 18A This is a schematic diagram of the main drive system 1D when the transmission path of the drive system is not connected in a closed loop manner. Figure 18B This is a diagram showing the body drive system 1D connected in a closed loop manner. Figure 19 This is a diagram showing the torque transmission flow in a cross-sectional unfolded view of the main drive system 1D connected in a closed loop.

[0280] The configuration of the main drive system 1D according to this embodiment differs from that according to the first embodiment in that the speed settings of the second differential gear 402 and the outer peripheral gear 403, which will be described below. Furthermore, in this embodiment, the connecting engagement portions 204b and 208b of the connecting members (204, 208) are configured to press the drum connector 63 along the normal rotation direction A1. In this embodiment, the connecting engagement portion 208b is configured to press the protrusion 63p of the drum connector 63 from the upstream side of the normal rotation direction A1. Figure 4 Other configurations of the body driving system 1D in this embodiment can be the same as those in the first embodiment.

[0281] like Figure 18AAs shown, when there is a gap G between the tooth surfaces 402b and 403b of the second differential gear 402 and the outer peripheral gear 403, it can be said that the main drive system 1D of this embodiment is not connected in a closed loop manner. With the gap G present, torque will not be transmitted from the second differential gear 402 to the outer peripheral gear 403. For example, this will occur immediately after the motor 301 starts. Figure 18A The state.

[0282] exist Figure 18A In this state, the driving force is sequentially transmitted from the motor 301 to the branch gear 302, the first drive gear 303, the connecting gear 201, the body-side connecting member 180, and the drum connecting member 63. Furthermore, the driving force is sequentially transmitted from the drum connecting member 63 to the engaging members (204, 208), the transmission shaft 209, the first differential gear 401, and the second differential gear 402. As a result, the second differential gear 402 rotates at a circumferential speed V5. The circumferential speed V5 is the speed at which the teeth of the second differential gear 402 move along the pitch circle of the second differential gear 402. Additionally, the circumferential speed V5 is determined by the angular velocity of the output shaft of the motor 301, the speed transmission ratio of the transmission path from the motor 301 to the second differential gear 402, and the pitch circle radius of the second differential gear 402. This speed transmission ratio is the ratio of the rotation angle of the second differential gear 402 to the rotation angle of the motor 301 when the second differential gear 402 is rotated by the motor 301.

[0283] At the same time, Figure 18A In this state, the driving force is transmitted sequentially from the motor 301 to the branch gear 302, the second drive gear 304, the load member gear 305, the fourth differential gear 405, the third differential gear 404, the differential shaft 406, the torque limiter 410, and the outer peripheral gear 403. Additionally, in Figure 18A In this state, since the outer peripheral gear 403 does not receive load from the second differential gear 402, slippage of the torque limiter 410 does not occur, and the outer peripheral gear 403 and the differential shaft 406 rotate together at an angular velocity R6. The angular velocity R6 is determined by the angular velocity of the output shaft of the motor 301 and the speed transmission ratio of the transmission path from the motor 301 to the differential shaft 406. This speed transmission ratio is the ratio of the rotation angle of the differential shaft 406 to the rotation angle of the output shaft of the motor 301 when the differential shaft 406 is rotated by the motor 301.

[0284] When the outer peripheral gear 403 rotates at an angular velocity R6 equal to the angular velocity of the differential shaft 406, the circumferential velocity of the outer peripheral gear 403 will be represented by V6. The circumferential velocity V6 is the speed at which the teeth of the outer peripheral gear 403 move along its pitch circle. The circumferential velocity V6 is expressed by multiplying the angular velocity R6 by the pitch circle radius of the outer peripheral gear 403.

[0285] Here, in Figure 18A In this state, the circumferential speed V5 of the second differential gear 402 is lower than the circumferential speed V6 of the outer gear 403 (V5 < V6). That is, unlike the first embodiment, the tooth movement speed of the outer gear 403 is higher than the tooth movement speed of the second differential gear 402. Therefore, it immediately enters the state after the motor 301 has just started. Figure 18A After that state, as a result of the teeth of the second differential gear 402 being caught up by the teeth of the outer peripheral gear 403, the tooth surfaces 402b and 403b come into contact with each other.

[0286] Therefore, as Figure 18B As shown, the tooth surface 402b of the second differential gear 402 contacts the tooth surface 403b of the outer peripheral gear 403. As a result of the contact between tooth surfaces 402b and 403b, torque is transmitted between the second differential gear 402 and the outer peripheral gear 403. Therefore, with tooth surfaces 402b and 403b in contact with each other, it can be said that the main drive system 1D of this embodiment is as follows: Figure 20 The connection shown is a closed loop.

[0287] It should be noted that, although the above has assumed that the second differential gear 402 is in Figure 18A The state of rotation at a circumferential speed V5 was described, but a second differential gear 402 can be used in... Figure 18A A configuration that remains stationary and does not rotate. That is, in... Figure 18A In this state, the torque along the normal rotation direction A1 does not need to be transmitted from the drum connector 63 to the engagement members (204, 208), and the engagement members (204, 208), the transmission shaft 209, the first differential gear 401, and the second differential gear 402 can remain stationary. Similarly, in this case, due to... Figure 18A In the state where the circumferential speed V5 (=0) of the second differential gear 402 is lower than the circumferential speed V6 of the outer gear 403, the tooth surfaces 402b and 403b come into contact with each other as a result of the teeth of the outer gear 403 catching up with the teeth of the second differential gear 402.

[0288] When the teeth of the outer peripheral gear 403 are like Figure 18B When the outer peripheral gear 403 catches up with the tooth of the second differential gear 402, it receives a reaction force from the tooth surface 402b of the second differential gear 402 via its tooth surface 403b and rotates at a circumferential velocity V5 equal to the circumferential velocity of the second differential gear 402. Simultaneously, the differential shaft 406 continues to rotate at an angular velocity R6. The angular velocity R5 of the outer peripheral gear 403 corresponding to the circumferential velocity V5 is lower than the angular velocity R6 of the differential shaft 406 (R5 < R6). That is, the angular velocity R5 of the outer ring 410a, which rotates integrally with the outer peripheral gear 403, is lower than the angular velocity R6 of the inner ring 410b, which rotates integrally with the differential shaft 406.

[0289] As described above, with the main drive system 1D connected in a closed loop, different angular velocities R5 and R6 are input to the outer ring 410a and inner ring 410b of the torque limiter 410, respectively, and the torque limiter 410 slips (relative rotation between the outer ring 410a and inner ring 410b). The torque limiter 410 allows different angular velocities R5 and R6 to be input to the outer ring 410a and inner ring 410b and absorbs the difference in angular velocity.

[0290] exist Figure 18B In such a state, such as Figure 19 As shown, the torque corresponding to the load generated by the torque limiter 410 is sequentially transmitted from the outer peripheral gear 403 to the second differential gear 402, the first differential gear 401, the transmission shaft 209, and the engagement members (204, 208). Then, the torque corresponding to the load generated by the torque limiter 410 is transmitted from the engagement members (204, 208) to the drum connector 63.

[0291] The torque corresponding to the load generated by the torque limiter 410 and transmitted from the connecting members (204, 208) to the drum connector 63 is less than the load used to drive the box P. Therefore, the remainder of the driving force required to drive the box P is supplied from the body-side connecting member 180 to the drum connector 63. That is, the box P receives the force (driving force) acting on the drum connector 63 in the normal rotation direction A1 from both the body-side connecting member 180 of the first drive transmission section 1D1 and the connecting members (204, 208) of the second drive transmission section 1D2.

[0292] Model of the body-driven system

[0293] Reference Figure 20 The torque transmission process in the body drive system 1D in the third embodiment is described. Figure 20 This is a model diagram illustrating the 1D body driving system of this embodiment. Figure 20 The torques used in the description are compared by using values ​​converted to torque acting on the output shaft of motor 301.

[0294] like Figure 20 As shown, the torque transmitted from motor 301 to the inner ring 410b of torque limiter 410 via motor-side transmission portion 1D2a of second drive transmission portion 1D2 will be expressed as T. TL3 The torque transmitted from the outer ring 410a of the torque limiter 410 to the drum connector 63 of the housing P via the housing-side transmission portion 1D2b of the second drive transmission portion 1D2 will be expressed as T. TL3 '.

[0295] As described above, since the angular velocity R5 of the outer ring 410a is lower than the angular velocity R6 of the inner ring 410b during image formation (R5 < R6), slippage (relative rotation) occurs between the outer ring 410a and the inner ring 410b during image formation. Torque T TL3 The torque required to overcome the friction between the outer ring 410a and the inner ring 410b, causing the inner ring 410b to rotate relative to the outer ring 410a. Torque T TL3 This corresponds to the torque applied to the outer ring 410a by the friction between the outer ring 410a and the inner ring 410b. In this embodiment, when comparing torque values ​​about the rotation axis of the motor 301, the torque value is at T. TL3 ' < T TL3 The relationship.

[0296] In this embodiment, the drum connector 63 receives torque (driving force, first force) along the normal rotation direction A1 from the first drive transmission portion 1D1, and also receives torque (driving force, second force) along the normal rotation direction A1 from the second drive transmission portion 1D2. In other words, the replaceable unit in this embodiment receives forces acting on the rotating member of the replaceable unit along the first rotation direction from both the first drive transmission portion 1D1 and the second drive transmission portion 1D2.

[0297] The force received by the body-side connector 180 from the drum connector 63 in this embodiment will be referred to as the connecting torque T. IF3 Additionally, the load required by the drive box P will be represented as T. p In this embodiment, the load T for box P is... p In other words, the torque T transmitted from the torque limiter 410 to the drum connector 63 TL3 The unmet residual torque is transmitted from the body-side connector 180 to the drum connector 63. That is, the connecting torque T... IF3 It can be represented by the following equation.

[0298] T IF3 = T p - T TL3 '

[0299] According to the above equation, since the driving force is transmitted via the second drive transmission section 1D2 including the torque limiter 410, the load acting on the first drive transmission section 1D1 can be reduced. That is, in the second reference example excluding the second drive transmission section 1D2 ( Figure 13C In the case of ), the connecting torque T IF "Equal to the load T of box P" p (T) IF = T p Therefore, the load T pThe load acts on gears, etc., included in the first drive transmission section 1D1. In contrast, the load acting on gears, etc., included in the first drive transmission section 1D1 of this embodiment is reduced to T. IF3 .

[0300] According to this embodiment, for example, even when the load T of box P is... p Larger or load T p Even if the load is temporarily increased due to external forces, it is unlikely that a large load will be applied to the gears and the like included in the first drive transmission section 1D1, and therefore deformation is unlikely to occur. For example, deformation of the gear teeth or deformation of the force transmission surface 180d of the body-side connecting member 180 is unlikely to occur. As a result, changes in the rotational speed input to the drum connecting member 63 via the first drive transmission section 1D1 caused by deformation of the components can be suppressed.

[0301] Advantages of this embodiment

[0302] As described above, according to this embodiment, an image forming apparatus including new elements related to the driving of the replaceable unit can be provided.

[0303] For example, according to this embodiment, the force (driving force) along the normal rotation direction A1 is transmitted to the drum connector 63 of the box P through multiple paths in the closed loop transmission path. Since the load acting on the components included in the transmission path can be reduced, changes in the driving speed caused by the deformation of the components can be suppressed.

[0304] Fourth embodiment

[0305] Figure 21A This is a model diagram of the body driving system 1D according to another embodiment (fourth embodiment) of this disclosure. Figure 21B This is a schematic diagram of planetary gear mechanism 500.

[0306] The planetary gear mechanism 500 is an example of a permissive mechanism including a first rotating member and a second rotating member in a closed-loop transmission path. The planetary gear mechanism 500 includes a first gear 500a, a second gear 500b, a third gear 500c, and a planetary gear 500p. Each of the first gear 500a, second gear 500b, and third gear 500c is rotatable about the planetary gear mechanism 500's revolution axis Ax and rotates relative to each other. The planetary gear 500p is rotatable about its rotation axis and revolves around the planetary gear 500p's revolution axis Ax.

[0307] like Figure 21BAs shown, the planetary gear mechanism 500 includes a sun gear 501, a ring gear 502, and a carrier 503 (planetary carrier). The sun gear 501 includes an external gear 501a that faces radially outward. The ring gear 502 includes an internal gear 502b disposed on the outer peripheral side of the sun gear 501 and facing radially inward. The carrier 503 rotatably supports the planetary gear 500p that engages with the external gear 501a and the internal gear 502a.

[0308] Figure 21A The first gear 500a (first rotating member) is one of the sun gear 501, the ring gear 502, and the carrier 503. The second gear 500b (second rotating member) is one of the other two of the sun gear 501, the ring gear 502, and the carrier 503, excluding the first gear 500a. The third gear 500c (third rotating member) is the remaining one of the sun gear 501, the ring gear 502, and the carrier 503, excluding the first gear 500a (first rotating member) and the second gear 500b (second rotating member). In other words, in the planetary gear mechanism 500, the first gear 500a, the second gear 500b, the third gear 500c, and the planetary gear 500p correspond to the functional parts of the permissive or differential mechanism.

[0309] The motor-side transmission section 1D2a is connected to the first gear 500a and the branch gear 302 (output section) of the planetary gear mechanism 500. Additionally, the box-side transmission section 1D2b is connected to the second gear 500b of the planetary gear mechanism 500 and the drum connector 63 (driven section) of the box P.

[0310] The first drive transmission section 1D1 and the second drive transmission section 1D2 are configured such that the angular velocity of rotation input to the third gear 500c when the drive drum connector 63 is different from the angular velocity input to the first gear 500a. The planetary gear mechanism 500 allows the sun gear 501, ring gear 502, and carrier member 503 to rotate relative to each other via the rotation of the planetary gear 500p. Furthermore, the planetary gear mechanism 500 is capable of transmitting force (torque) between the first gear 500a and the second gear 500b. That is, the planetary gear mechanism 500 is an example of a permissive mechanism (differential mechanism) capable of transmitting driving force between the first rotating member and the second rotating member and configured to allow for a change in the ratio between the first angular velocity of the first rotating member and the second angular velocity of the second rotating member.

[0311] In addition, Figure 21AIn the example, the third gear 500c (third rotating member) is connected to the load member 306. In the planetary gear mechanism 500, when the angular velocities of two of the three rotating members (sun gear, ring gear, and load member) rotating around the revolution axis Ax are given, the angular velocity of the remaining member is determined. In this embodiment, the first gear 500a (first rotating member) and the second gear 500b (second rotating member) are connected to the branch gear 302 (output section) via a closed-loop transmission path. That is, the first gear 500a is connected to the branch gear 302 (output section) via the motor-side transmission section 1D2a. Furthermore, the second gear 500b is connected to the branch gear 302 via the box-side transmission section 1D2b, the driven part of the box P, and the first drive transmission section 1D1. Therefore, when driven by motor 301, the angular velocities of the first gear 500a (first rotating member) and the second gear 500b (second rotating member) are determined based on the angular velocity of the branch gear 302 (output part), and further, the angular velocity of the third gear 500c (third rotating member) is determined.

[0312] According to this configuration, the planetary gear mechanism 500 can absorb the difference in angular velocity input through the closed loop transmission path, and the driving force of the motor 301 can be transmitted to the load member 306, which is the driving target in addition to the box P.

[0313] Furthermore, when the load member 306 is driven, at least a portion of the load received by the third gear 500c from the load member 306 is transmitted from the third gear 500c to the second gear 500b in the planetary gear mechanism 500. This load is also transmitted from the second gear 500b to the drum connector 63 via the box-side transmission portion 1D2b as a force (braking force) acting in the opposite direction to the normal rotation direction A1. That is, at least a portion of the load of the load member 306 is transmitted to the box P (unit) as a braking force (second force) via the third gear 500c (third rotating member), the second gear 500b (second rotating member), and the box-side transmission portion 1D2b (unit-side transmission portion). According to this configuration, similar to the first and second embodiments, the premature rotation of the drum connector 63 and the photosensitive drum 61 can be suppressed, and the box P can be driven at a more stable driving speed.

[0314] The planetary gear mechanism 500 can be positioned similarly to the torque limiter 410 in the first to third embodiments. For example, the planetary gear mechanism 500 is configured such that the revolution axis Ax is parallel to the axis M1 of the drive transmission unit 200 and extends through a position away from the axis M1 (see [link to relevant documentation]). Figure 5A , Figure 7A and Figure 7BIt should be noted that the revolution axis Ax of the planetary gear mechanism 500 can be coaxial with axis M1.

[0315] It should be noted that the connection relationships between the first gear 500a, the second gear 500b, and the third gear 500c, the motor-side transmission portion 1D2a and the box-side transmission portion 1D2b of the second drive transmission portion 1D2, and the load member 306 are not limited to the above-described connection relationships. That is, the combination of connections between the three rotating components (sun gear, ring gear, and load-bearing member) of the planetary gear mechanism 500, the motor-side transmission portion 1D2a, the box-side transmission portion 1D2b, and the load member 306 can be changed.

[0316] For example, the first gear 500a can be connected to the motor-side transmission section 1D2a, the third gear 500c can be connected to the box-side transmission section 1D2b, and the second gear 500b can be connected to the load member 306. (This is repeated four times in the original text.) In addition, the third gear 500c can be connected to the motor-side transmission section 1D2a, the first gear 500a can be connected to the box-side transmission section 1D2b, and the second gear 500b can be connected to the load member 306.

[0317] Advantages of this embodiment

[0318] As described above, according to this embodiment, an image forming apparatus including new elements related to the driving of the replaceable unit can be provided.

[0319] As described above, box P is an example of a "unit" that is not necessarily detachable from the device body 1A. That is, according to this embodiment, an image forming apparatus that includes new elements related to the driving of units in the image forming apparatus can be provided.

[0320] For example, according to this embodiment, the driving force in the normal rotation direction A1 and the braking force in the opposite direction can be transmitted to the drum connector 63 of the housing P via a closed-loop transmission path. As a result, the premature rotation of the drum connector 63 and the photosensitive drum 61 can be suppressed, and the housing P can be driven at a more stable driving speed. Specifically, in this embodiment, the above advantages can be achieved by a configuration in which a portion of the load of the load member 306 is transmitted to the drum connector 63 as a braking force (driving force) via the planetary gear mechanism 500.

[0321] Fifth Embodiment

[0322] Figure 22A and Figure 22B These are diagrams illustrating the body drive system 1D according to yet another embodiment (fifth embodiment). The difference between this embodiment and the first embodiment is that, during image formation, the rotational directions of the inner ring 410b of the torque limiter 410, the third differential gear 404, the fourth differential gear 405, and the differential shaft 406 are opposite to those in the first embodiment (see [reference]). Figure 11A and Figure 11B ).

[0323] Immediately after motor 301 starts, such as Figure 22A As shown, the second differential gear 402 rotates counterclockwise at a circumferential speed V1, and the outer peripheral gear 403 rotates clockwise at a circumferential speed V2'. The outer peripheral gear 403 and the outer ring 410a rotate integrally with the inner ring 410b and the differential shaft 406 at an angular velocity R1. As a result, as... Figure 22B As shown, the tooth surface 403a of the outer peripheral gear 403 and the tooth surface 402a of the second differential gear 402 are in contact with each other.

[0324] When the tooth surfaces 403a of the outer peripheral gear 403 and 402a of the second differential gear 402 come into contact with each other, the outer ring 410a of the torque limiter 410 overcomes the friction between the outer ring 410a and the inner ring 410b and rotates at a circumferential speed V1. At this time, the outer ring 410a rotates in the opposite direction to the rotation direction of the inner ring 410b with an angular velocity R1 corresponding to the circumferential speed V1.

[0325] exist Figure 22B In the current state, the load generated by the slippage of the torque limiter 410 is transmitted via the second differential gear 402, the first differential gear 401, the transmission shaft 209, and the connecting members (204, 208). Then, the load generated by the slippage of the torque limiter 410 is transmitted to the drum connector 63 (driven part) as a force (braking force) in the opposite direction to the normal rotation direction A1.

[0326] As described above, with the main drive system 1D connected in a closed loop, different angular velocities R1 and R2' are input to the outer ring 410a and inner ring 410b of the torque limiter 410, respectively, and the torque limiter 410 slips (relative rotation between the outer ring 410a and inner ring 410b). Specifically, in this embodiment, the rotation directions of the outer ring 410a and inner ring 410b are opposite to each other. The torque limiter 410 allows different angular velocities R1 and R2' to be input to the outer ring 410a and inner ring 410b and absorbs the difference in angular velocity. In addition, similar to the first embodiment, the torque limiter 410 in this embodiment generates a load for applying braking force to the drum connector 63 through the relative rotation between the outer ring 410a and inner ring 410b.

[0327] With this configuration, similar advantages to those of the first embodiment can also be obtained.

[0328] Other modifications

[0329] Although the driving of the photosensitive drum 61 disposed in the cartridge P has been described primarily as an example in each of the above embodiments, the application of the technology disclosed herein is not limited to the photosensitive drum 61 and the cartridge P. The "replaceable unit" is not limited to the cartridge P including the photosensitive drum 61, but may be, for example, the transfer unit 40. The driving target is not limited to the photosensitive drum 61, but may be, for example, the drive roller 46 that rotates the belt 41.

[0330] According to this disclosure, an image forming apparatus may be provided that includes novel elements related to the driving of a replaceable unit.

[0331] Overview of this disclosure

[0332] This disclosure includes at least the following.

[0333] (Configuration A1)

[0334] An image forming apparatus comprising:

[0335] A replaceable unit, the replaceable unit including a driven portion; and

[0336] The device body, wherein the replaceable unit is detachably attached to the device body, the device body comprising

[0337] (i) A drive unit, the drive unit comprising a drive source configured to generate a driving force and an output portion configured to output the driving force.

[0338] (ii) A first drive transmission section, the first drive transmission section being connected to the output section and the replaceable unit, and

[0339] (iii) A second drive transmission section, the second drive transmission section including a permissive mechanism and connected to the output section and the replaceable unit, the permissive mechanism including a first rotating member and a second rotating member and configured to transmit a driving force between the first rotating member and the second rotating member and to allow a change in the ratio between a first angular velocity of the first rotating member and a second angular velocity of the second rotating member.

[0340] The driving force transmission path includes a closed loop, which comprises the driven portion, the output portion, the first driving transmission portion, and the second driving transmission portion.

[0341] The first drive transmission portion and the second drive transmission portion are configured such that when the driven portion is driven by the drive source, the first angular velocity is different from the second angular velocity.

[0342] (Configuration A2)

[0343] According to the image forming apparatus of configuration A1, the first rotating member and the second rotating member are configured to rotate about the same rotation axis.

[0344] (Configuration A3)

[0345] According to the image forming apparatus of configuration A1, wherein the permissive mechanism is configured to generate a load by friction generated when the first rotating member and the second rotating member rotate relative to each other.

[0346] (Configuration A4)

[0347] According to any one of configurations A1 to A3, the image forming apparatus wherein the permissive mechanism is a torque limiter configured such that when a torque above a predetermined value is applied between the first rotating member and the second rotating member, the first rotating member and the second rotating member rotate relative to each other.

[0348] (Configuration A5)

[0349] The image forming apparatus according to any one of configurations A1 to A3

[0350] The permissive mechanism includes a sun gear, a ring gear, planetary gears, and a support member. The ring gear is disposed on the outer periphery of the sun gear. The planetary gears engage with the sun gear and the ring gear. The support member supports the planetary gears.

[0351] The first rotating member is one of the sun gear, the ring gear, and the carrier member, and

[0352] The second rotating member is one of the sun gear, the ring gear, and the carrier, excluding the first rotating member.

[0353] (Configuration A6)

[0354] The image forming apparatus according to any one of configurations A1 to A5 further includes a load member, the driving force of the drive source being transmitted to the load member via at least a portion of the closed loop.

[0355] (Configuration A7)

[0356] An image forming apparatus comprising:

[0357] A replaceable unit, the replaceable unit including a driven portion; and

[0358] The device body, wherein the replaceable unit is detachably attached to the device body, the device body comprising

[0359] (i) A drive unit, the drive unit comprising a drive source configured to generate a driving force and an output portion configured to output the driving force.

[0360] (ii) A first drive transmission section, the first drive transmission section being connected to the output section and the replaceable unit, and

[0361] (iii) A second drive transmission section, the second drive transmission section including a differential mechanism and connected to the output section and the replaceable unit, the differential mechanism including a first rotating member and a second rotating member and configured to allow the first rotating member and the second rotating member to rotate relative to each other.

[0362] The driving force transmission path includes a closed loop, which comprises the driven portion, the output portion, the first driving transmission portion, and the second driving transmission portion.

[0363] The first drive transmission portion and the second drive transmission portion are configured such that, when the driven portion is driven by the drive source, the first angular velocity of the first rotating member is different from the second angular velocity of the second rotating member, and

[0364] The first rotating member and the second rotating member are configured to rotate about the same axis of rotation.

[0365] (Configured with A8)

[0366] An image forming apparatus comprising:

[0367] A replaceable unit, the replaceable unit including a driven portion; and

[0368] The device body, wherein the replaceable unit is detachably attached to the device body, the device body comprising

[0369] (i) A drive unit, the drive unit comprising a drive source configured to generate a driving force and an output portion configured to output the driving force.

[0370] (ii) A first drive transmission section, the first drive transmission section being connected to the output section and the replaceable unit, and

[0371] A second drive transmission section, including a differential mechanism and connected to the output section and the replaceable unit, the differential mechanism including a first rotating member and a second rotating member and configured to allow the first rotating member and the second rotating member to rotate relative to each other.

[0372] The driving force transmission path includes a closed loop, which comprises the driven portion, the output portion, the first driving transmission portion, and the second driving transmission portion.

[0373] The first drive transmission portion and the second drive transmission portion are configured such that, when the driven portion is driven by the drive source, the first angular velocity of the first rotating member is different from the second angular velocity of the second rotating member, and

[0374] The differential mechanism is configured to generate a load through friction generated when the first rotating member and the second rotating member rotate relative to each other.

[0375] (Configured with A9)

[0376] The image forming apparatus according to any one of configurations A1 to A8

[0377] The driven portion includes a rotating member configured to rotate in a first rotational direction by the drive source, and

[0378] The replaceable unit is configured to receive a first force from the first drive transmission portion and a second force from the second drive transmission portion, the first force acting on the rotating member along a first rotation direction and the second force acting on the rotating member along a second rotation direction opposite to the first rotation direction.

[0379] (Configured with A10)

[0380] The image forming apparatus according to configuration A9

[0381] The second drive transmission section includes: (a) a unit-side transmission section connected to the first rotating member and the driven member; and (b) a drive source-side transmission section connected to the output member and the second rotating member.

[0382] The unit-side transmission portion is configured to transmit at least a portion of the force received by the first rotating member from the second rotating member to the driven portion when the first rotating member and the second rotating member rotate relative to each other.

[0383] (Configured with A11)

[0384] According to the image forming apparatus of configuration A10, wherein when the driven portion is driven by the driving source, the first angular velocity is higher than the second angular velocity.

[0385] (Configured with A12)

[0386] According to the image forming apparatus described in configuration A10 or A11, it further includes:

[0387] A load member, which is connected to the drive source-side transmission section,

[0388] The drive source-side transmission portion is configured to transmit at least a portion of the force received by the second rotating member from the first rotating member to the load member when the first rotating member and the second rotating member rotate relative to each other.

[0389] (Configured with A13)

[0390] The image forming apparatus according to any one of configurations A1 to A8

[0391] The driven portion includes a rotating member configured to rotate in a first rotational direction by the drive source, and

[0392] The replaceable unit is configured to receive a third force from the second drive transmission portion and a fourth force from the first drive transmission portion, the third force acting on the rotating member along a first rotation direction and the fourth force acting on the rotating member along a second rotation direction opposite to the first rotation direction.

[0393] (Configured with A14)

[0394] The image forming apparatus according to configuration A13

[0395] The first drive transmission section is configured to transmit a portion of the force applied from the second drive transmission section to the driven section from the driven section to the output section.

[0396] The output section is a gear, and

[0397] When the driven part is driven by the drive source, the force transmitted from the driven part via the first drive transmission part acts on the gear in the same direction as the rotation direction of the gear.

[0398] (Configured with A15)

[0399] According to the image forming apparatus of configuration A14, wherein when the driven portion is driven by the driving source, the first angular velocity is lower than the second angular velocity.

[0400] (Configured with A16)

[0401] The image forming apparatus according to any one of configurations A13 to A15

[0402] The replaceable unit includes a force receiving portion configured to receive force from the first drive transmission portion.

[0403] The first drive transmission section includes a first gear and a second gear, wherein the second gear is configured to engage with the first gear.

[0404] When the driven part is driven by the drive source, the first tooth surface of the first gear abuts against the second tooth surface of the second gear, and

[0405] The first drive transmission portion is configured such that when an external force is applied that causes the rotating member to rotate at a speed higher than the driving speed of the rotating member driven by the drive source in a first rotation direction, the contact between the first tooth surface and the second tooth surface is maintained, and the force acting between the force receiving portion of the replaceable unit and the first drive transmission portion increases according to the external force.

[0406] (Configured with A17)

[0407] The image forming apparatus according to any one of configurations A1 to A8

[0408] The driven portion includes a rotating member configured to rotate in a first rotational direction by the drive source, and

[0409] The replaceable unit is configured to receive forces acting on the rotating member along a first rotational direction from both the first drive transmission portion and the second drive transmission portion.

[0410] (Configuration A18)

[0411] According to any one of configurations A1 to A17, the image forming apparatus, wherein the replaceable unit includes a photosensitive drum, and the photosensitive drum is rotated by the driving force.

[0412] (Configuration B1)

[0413] An image forming apparatus comprising:

[0414] Unit, the unit including a driven part;

[0415] A drive unit, the drive unit including a drive source configured to generate a drive force and an output portion configured to output the drive force;

[0416] A first drive transmission section, the first drive transmission section being connected to the output section and the unit; and

[0417] The second drive transmission section includes a planetary gear mechanism and is connected to the output section and the unit.

[0418] The driving force transmission path includes a closed loop, which includes the driven part, the output part, the first driving transmission part, and the second driving transmission part.

[0419] (Configuration B2)

[0420] The image forming apparatus according to configuration B1

[0421] The second drive transmission section includes a drive source-side transmission section connected to the output section and a unit-side transmission section connected to the unit.

[0422] The first drive transmission portion, the drive source-side transmission portion, and the unit-side transmission portion are configured such that, when the driven portion is rotatably driven by the drive source, the angular velocity of the rotation about the revolution axis of the planetary gear mechanism input to the planetary gear mechanism via the drive source-side transmission portion is different from the angular velocity of the rotation about the revolution axis of the planetary gear mechanism input to the planetary gear mechanism via the unit-side transmission portion.

[0423] (Configuration B3)

[0424] The image forming apparatus according to configuration B2

[0425] The planetary gear mechanism includes a sun gear, a ring gear, planetary gears, and a support member. The ring gear is disposed on the outer periphery of the sun gear. The planetary gears engage with the sun gear and the ring gear. The support member supports the planetary gears.

[0426] Wherein, one of the sun gear, the ring gear, and the carrier is a first rotating member connected to the unit-side transmission portion, and

[0427] The sun gear, the ring gear, and the carrier, excluding the first rotating member, are all second rotating members connected to the drive source side transmission portion.

[0428] (Configuration B4)

[0429] The image forming apparatus according to configuration B3

[0430] The sun gear, the ring gear, and the carrier member, excluding the first and second rotating members, are designated as the third rotating member.

[0431] The image forming apparatus further includes a load member, the driving force of which is transmitted to the load member via the third rotating member.

[0432] (Configuration B5)

[0433] According to the image forming apparatus described in configuration B4, the load member is a conveyor roller configured to convey recording material.

[0434] (Configuration B6)

[0435] The image forming apparatus according to configuration B5

[0436] The driven portion includes a rotating member that rotates along a first rotation direction via the drive source, and

[0437] The unit is configured to receive a first force from the first drive transmission portion and a second force from the second drive transmission portion, the first force acting on the rotating member along a first rotation direction and the second force acting on the rotating member along a second rotation direction opposite to the first rotation direction.

[0438] (Configuration B7)

[0439] According to the image forming apparatus of configuration B6, at least a portion of the load of the load member is transmitted to the unit as the second force via the third rotating member, the first rotating member and the unit-side transmission portion.

[0440] (Configuration B8)

[0441] According to the image forming apparatus of configuration B6 or B7, the unit includes a first surface configured to receive the first force from the first drive transmission portion and a second surface configured to receive the second force from the second drive transmission portion.

[0442] (Configuration B9)

[0443] The image forming apparatus according to any one of configurations B1 to B8, wherein the unit includes a photosensitive drum configured to rotate by the driving force.

[0444] Other embodiments

[0445] While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the following claims should be interpreted in the broadest possible sense to include all such modifications and equivalent structures and functions.

Claims

1. An image forming apparatus comprising: a replaceable unit including a driven portion; and an apparatus main body to which the replaceable unit is detachably attached, the apparatus main body including (i) a drive unit including a drive source configured to generate a driving force and an output portion configured to output the driving force, (ii) a first drive transmission portion connected to the output portion and the replaceable unit, and (iii) a second drive transmission portion including an accommodation mechanism and connected to the output portion and the replaceable unit, the accommodation mechanism including first and second rotary members and configured to transmit the driving force between the first and second rotary members and to accommodate a change in a ratio between a first angular velocity of the first rotary member and a second angular velocity of the second rotary member, wherein a transmission path of the driving force includes a closed loop including the driven portion, the output portion, the first drive transmission portion, and the second drive transmission portion, and wherein the first drive transmission portion and the second drive transmission portion are configured such that, in a case where the driven portion is driven by the drive source, the first angular velocity is different from the second angular velocity.

2. The image forming apparatus according to claim 1, wherein the first and second rotary members are configured to rotate around the same rotation axis.

3. The image forming apparatus according to claim 1 or 2, wherein the accommodation mechanism is configured to generate a load by friction generated when the first and second rotary members relatively rotate.

4. The image forming apparatus according to claim 1 or 2, wherein the accommodation mechanism includes a sun gear, a ring gear provided on an outer peripheral side of the sun gear, a planetary gear engaged with the sun gear and the ring gear, and a carrier supporting the planetary gear, wherein the first rotary member is one of the sun gear, the ring gear, and the carrier, and wherein the second rotary member is one of the other two of the sun gear, the ring gear, and the carrier excluding the first rotary member.

5. The image forming apparatus according to claim 1 or 2, wherein the driven portion includes a rotary member configured to rotate in a first rotation direction by the drive source, and wherein the replaceable unit is configured to receive a first force acting on the rotary member in a first rotation direction from the first drive transmission portion and a second force acting on the rotary member in a second rotation direction opposite to the first rotation direction from the second drive transmission portion.

6. The image forming apparatus according to claim 5, The second drive transmission portion includes: (a) a unit-side transmission portion connected to the first rotary member and the driven portion; and (b) a drive-source-side transmission portion connected to the output portion and the second rotary member, and wherein the unit-side transmission portion is configured to transmit at least a portion of a force received by the first rotary member from the second rotary member to the driven portion in a case where the first rotary member and the second rotary member relatively rotate.

7. The image forming apparatus according to claim 6, wherein the first angular velocity is higher than the second angular velocity in a case where the driven portion is driven by the drive source.

8. The image forming apparatus according to claim 7, further comprising: a load member connected to the drive-source-side transmission portion, wherein the drive-source-side transmission portion is configured to transmit at least a portion of a force received by the second rotary member from the first rotary member to the load member in a case where the first rotary member and the second rotary member relatively rotate.

9. The image forming apparatus according to claim 1 or 2, wherein the driven portion includes a rotary member configured to rotate in a first rotation direction by the drive source, and wherein the replaceable unit is configured to receive a third force acting on a rotary member in a first rotation direction from the second drive transmission portion and a fourth force acting on a rotary member in a second rotation direction opposite to the first rotation direction from the first drive transmission portion.

10. The image forming apparatus according to claim 9, wherein the first drive transmission portion is configured to transmit a portion of a force applied to the driven portion from the second drive transmission portion from the driven portion to the output portion, wherein the output portion is a gear, and wherein a force direction of a force transmitted from the driven portion via the first drive transmission portion on the gear is the same as a rotation direction of the gear in a case where the driven portion is driven by the drive source.

11. The image forming apparatus according to claim 10, wherein the first angular velocity is lower than the second angular velocity in a case where the driven portion is driven by the drive source.

12. The image forming apparatus according to claim 1 or 2, wherein the driven portion includes a rotary member configured to rotate in a first rotation direction by the drive source, and wherein the replaceable unit is configured to receive a force acting on a rotary member in a first rotation direction from both the first drive transmission portion and the second drive transmission portion.

13. An image forming apparatus comprising: a replaceable unit including a driven portion; and an apparatus main body to which the replaceable unit is detachably attached, the apparatus main body including (i) a drive unit including a drive source configured to generate a drive force and an output portion configured to output the drive force, (ii) a first drive transmission portion connected to the output portion and the replaceable unit, and (iii) a second drive transmission portion connected to the replaceable unit and the driven portion. (iii) a second drive transmission portion including a differential mechanism and connected to the output portion and the replaceable unit, the differential mechanism including a first rotary member and a second rotary member and configured to permit relative rotation of the first rotary member and the second rotary member, wherein a transmission path of a driving force includes a closed loop including the driven portion, the output portion, the first drive transmission portion, and the second drive transmission portion, wherein the first drive transmission portion and the second drive transmission portion are configured such that, in a case where the driven portion is driven by the driving source, a first angular velocity of the first rotary member is different from a second angular velocity of the second rotary member, and wherein the first rotary member and the second rotary member are configured to rotate around the same rotation axis.

14. An image forming apparatus comprising: a unit including a driven portion; a driving unit including a driving source configured to generate a driving force and an output portion configured to output the driving force; a first drive transmission portion connected to the output portion and the unit; and a second drive transmission portion including a planetary gear mechanism and connected to the output portion and the unit, wherein a transmission path of the driving force includes a closed loop including the driven portion, the output portion, the first drive transmission portion, and the second drive transmission portion.

15. The image forming apparatus according to claim 14, wherein the second drive transmission portion includes a driving source side transmission portion connected to the output portion and a unit side transmission portion connected to the unit, and wherein the first drive transmission portion, the driving source side transmission portion, and the unit side transmission portion are configured such that, in a case where the driven portion is rotationally driven by the driving source, an angular velocity of rotation around a revolution axis of the planetary gear mechanism input to the planetary gear mechanism via the driving source side transmission portion is different from an angular velocity of rotation around the revolution axis input to the planetary gear mechanism via the unit side transmission portion.

16. The image forming apparatus according to claim 15, wherein the planetary gear mechanism includes a sun gear, a ring gear provided on an outer peripheral side of the sun gear, a planetary gear engaged with the sun gear and the ring gear, and a carrier supporting the planetary gear, wherein one of the sun gear, the ring gear, and the carrier is a first rotary member connected to the unit side transmission portion, and wherein one of the other two of the sun gear, the ring gear, and the carrier excluding the first rotary member is a second rotary member connected to the driving source side transmission portion.

17. The image forming apparatus according to claim 16, ​ one of the sun gear, the ring gear, and the carrier other than the first rotary member and the second rotary member is a third rotary member, and wherein the image forming apparatus further includes a load member to which a driving force of the driving source is transmitted via the third rotary member.

18. The image forming apparatus according to claim 17, wherein the driven portion includes a rotary member that is rotated in a first rotation direction by the driving source, and wherein the unit is configured to receive a first force from the first driving transmission portion and a second force from the second driving transmission portion, the first force acting on the rotary member in a first rotation direction, the second force acting on the rotary member in a second rotation direction opposite to the first rotation direction.

19. The image forming apparatus according to claim 18, wherein at least a portion of a load of the load member is transmitted to the unit as the second force via the third rotary member, the first rotary member, and the unit-side transmission portion.

20. The image forming apparatus according to any one of claims 14 to 19, wherein the unit includes a photosensitive drum configured to be rotated by the driving force.

Images